Janet & Linda, so true! It's not just parents of difficult children who go through this - it's everybody, on almost every topic. With our parents it was money. Even with my (much older) siblings, they were all horrified when I went back to work 12 weeks after each child. They accused us of being greedy, of being materialistic. I said we had a mortgage to pay. They said, "Sell that house and buy a cheaper one."
I replied, "You can't GET a cheaper one that wouldn't need an equivalent amount (or more) of money to fix it up so it is habitable."
They disbelieved me until THEY looked around at real estate. Then slowly, their lives changed and they had to send the at-home parent back to work, to pay the bills. My siblings' criticism stopped. Parental criticism didn't. Then I became disabled and HAD to stay home. That was a whole other ball game.
When we first saw problems with our kids, at first it was blamed on parenting. It was because I had gone back to work. Then it was because I was 'malingering'. Then it was, "there's nothing wrong, you just need more experience as parents." All said kindly, of course.
One point I need to emphasise here - when you discover you have a family member with a disability or an illness, everybody involved has to go through a grieving process. And the first stage of grief is denial.
We all grieve in our own way and in our own time. Those furthest away from the problem are slowest to begin the grief process. As a result, we've worked through denial, to anger, then bargaining and almost reached acceptance while other family members are still stuck on denial. If you're coming to terms with acceptance and having to handle questions and comments from family members desperate for you to validate their denial, it makes it very difficult to cope emotionally.
Just recognise - the depth of their denial is often a measure of how much they care. They would rather believe you temporarily insane or incompetent, than in pain or suffering. If your suffering is perceived to be YOUR fault, they feel better but still try to convince you to wise up and fix it.
It's natural. Some friends and family never move past denial. This is sad because it will eventually alienate, unless you find another way to cope with them. Sometimes simply agreeing that some topics are permanently off limits is a way to continue family relationships that are otherwise getting strained.
My father had no concept of how fast inflation had hit, in the late 70s. He had married off a succession of daughters from the mid 60s onwards. There was a gap before husband & I married and he had lost touch with how much it was going to cost. He made us what he considered to be a generous offer. "Here's $100. Use this to pay for your wedding reception, and anything left over you can keep as a wedding present."
husband & I looked at each other and tried to hide the horror. We were poor students, only recently in the workforce and earning $100 a week each. We said nothing to him, just began looking for a place we could afford. I knew my father wanted us to invite the whole huge family and book a good reception place and not simply hire a couple of trestle tables and ask wedding guests to bring a plate (we seriously considered this and it was in our list of calculated figures), so we hoped he would get in touch with reality. The upmarket reception places were charging $20 a head. We found one we were happy with that only charged $8 a head. But the booking fee alone took the whole $100. When my father asked how we were going in our search, I laid ALL the figures down in front of him, including prices for the same reception places my sisters had used. By using the figures from places he'd previously paid for, he got his big taste of reality, and not from me. By this stage husband & I had left the room to allow him to swear in peace. When he finally emerged he was still white around the gills but thanks us for choosing a place with a good reputation but low cost. Clearly, he said, we had done our homework well and he would of course pay for it all. We heaved a big sigh of relief - we would have still been paying of the loan if we had done it ourselves back then.
So my final advice - never argue with them. Just leave the facts lying around. When they're ready to absorb the information they will do it in their own time. Unfortunately, for some this is never.