None of you can have Johnny. easy child 2/difficult child 2 has dibs on him.
But to be serious, you have some really good ammunition here with husband. And please be aware, I am not coming from a male-bashing point of view. Even the best marriage does not mean you both have to be in complete agreement or fully informed and understanding each of the other; only that you're prepared to make the effort once you realise that effort must be made.
You have a choice to accept what he has said (and labelled YOU with) or to not take that rubbish from him and stand up for yourself. Politely, in a friendly but firm manner, but still stand up to it. If my husband is reading this (and I'm sure he is, he always does when he can) then I think he can already predict how I would reply to him if he tried that line with me.
"Honey, you think I'm getting her assessed to give me a chance to get back to work - frankly, whether you think that or not, I really don't care. As you know, we discussed this and it has been MY choice always, whether to stay home or not. Other mothers of children this age should be able to work at least part-time - you just acknowledged that an assessment could allow me to get a job. This means you accept that there IS a chance she has a diagnosable, treatable disorder.
She is our child and I know we both love her. But it seems that only I am actually trying to DO anything. Forget my motivation - the end result should be a child given a better chance. Now you're always critical, but I'm the one digging up information which for various reasons, you do not read. I accept that you're busy because you're the breadwinner; that's fine. But you must also accept that I am doing MY job, and let me get on with it without being criticised. If you have serious concerns, then read the information I give you, before you criticise it. That is the professional way to assess the validity of this option or that, as is understood in the workplace.
I am trying to raise our child as best I can. I'd like you on board with this. I will help by making it short and simple for you, if you like. But if you do not read the information or even listen to it, then don't criticise."
This is equivalent to an office manager being told of new safety regulations coming into force and then refusing to acquaint himself with them because he feels he's been in the job long enough to know what he's doing, thank you very much. And when someone files a safety complaint against him because he did not follow those new safety regulations, he has absolutely not got a leg to stand on. Nothing can justify this negligence. Not even an inability to read - he could have got someone else to read it to him, or even delegated the implementation of the safety procedures. But as manager, it is HIS responsibility.
Your daughter is your joint responsibility. If he has delegated it to you in the past then he cannot complain now, if you are moving in a different direction. He is going to have to run to catch up, familiarising himself with all the landmarks and features of the landscape along the way. fast track learning - or shut up and let you do it yourself, and GIVE YOU CREDIT for the professional hours you put into your child.
Stand up for yourself. You are a good parent. He is an ostrich, in that he is sticking his head in the sand. NOT like an ostrich, in that he does nothing for his child except pay for the food on the table and the roof over the heads.
And a final suggested compromise with your husband - offer to explain "The Explosive Child" methods to him, and/or to give him a summary of it.
For his own reasons, my husband couldn't read it either. But he did listen while I explained it to him and he has followed my lead (it has taken time and we make mistakes still). My husband is a good man who recognises and values what I do, even though I do sometimes have to remind him when he and we have been having a really bad day in our respective jobs (as in, me with the kids).
But me writing a summary, or explaining it to him - that was valuable to ME, as well as him, because it helped to really lock the information and techniques into my head. End result- valuable to the kids, too.
Of course my husband was sceptical. So was I, at first. But it is seeing the way it works, recognising it in action, that slowly makes its way into the brain that this method, when adapted to the particular child, can and often does help.
As for the "no medications" - would he refuse to give your child insulin, should it turn out that they have Type 1 diabetes? Of what if your daughter is diagnosed bipolar?
My response to that - "Then it's a good thing that you have handed responsibility over to me, because I at least will have informed understanding before a decision as black and white as that is made."
He can also have informed understanding, but he'd better get a move on. It was HIS choice to remain ignorant, not yours to keep him in the dark. DO NOT let him dump this back on you or blame you in any way. DO NOT take any of this rubbish on board personally. And when you CAN keep your emotional distance from the hurt he is trying to throw your way, you will find you can cope with his diatribes much more easily. DO NOT be afraid of making him angry but similarly, do not goad him. He is a father who loves his daughter and finds it hard to accept there is anything wrong with her. It hurts him to hear of the possibility. It's easier to blame you for doing a bad job.
And the last resort - one my sister used with great success - if he continues to insist that you've been doing a bad job, then challenge him to do better. YOU go back to the paid workforce while HE becomes the house parent. Set ground rules - he must do everything he expected you to do. No leaving the housework entirely for you to come home to. It has to be a complete swap - he has to deal with the school and phone calls, he has to make sure that she gets to all her after-school activities. HE has to look after the washing, the cooking, the shopping... My sister successfully swapped with her husband after he had been complaining that the house was never tidy. And, surprise surprise! He came up with the goods. The house was tidy, he did the washing, shopping, ironing, SOME of the cooking and all the running around and did it well, better than my sister had. And he was happy doing it. And she was happier back at work. AND she could earn more than him so they did better financially (a bonus).
I've known other couples to do this for a year each at a time. In about half the cases at least, the husband has ended up choosing to remain the house parent, doing odd jobs in the neighbourhood when the kids are at school. One of these fathers began our Community Garden and even though their children are now in high school, he goes to the local primary school and talks to them about the community garden they can see in the school grounds. He discovered an interest and a talent for something very different and has made a success of it (and their children).
It mightn't work like this, but be prepared to follow through if he takes up the challenge. Support him (as he never supported you) and this will SHOW him how to behave (which is how Ross Greene's stuff works).
And if all else fails - use the Ross Greene methods on husband!