Darlin, Cut yourself some slack! This will not be the first time or the last time a 5yo doesn't know his letters/numbers/yaddas and whatchywiggies.
He is 5. 5. Let that sink in.
What is he interested in? What does he like? Does he learn more from seeing and writing/drawing, from sensory stuff using his hands, from hearing, or from a bunch of that kind of stuff.
If he has had help, and now they (these "they"s that think about our kids drive me bats!)want him to do it with-o help, if he still can't, they still have to help him. (I hope this made sense).
My little guy is a delightful guy until you want him to do something with his hands or run around awhile. Something like, oh, writing. It HURTS and his brain doesn't get it. So it makes for rough days at my house. This is my 7 yo little guy.
I have worked with and known people who where so incredibly smart, but writing, &/or reading was a huge challenge. It is doable.
For now just take deep breathes. Betcha you are not the only mom with these worries. My sister in law was freaking because the test to get into their local public Kdg came back with her son flunking it. When we found out what the deal breaker was, nephew refused to acknowledge a picture of someone in a tie as a daddy, or reckognize that ties meant daddies to the school system.
My nephew had NEVER seen his dad in a tie. brother in law hates them and won't wear them. And he is a plumber - a really good one! School took its silly rules away and my nephew went to school with his friends.
Hugs,
Susie
