Responding to son really struggling with bipolar diagnosis now probable autism

Hi, I've had a couple of queries over the past 2 years about my adult son with bipolar, anxieties etc & some really hard times for him. The responses have been very helpful thanks. The problem now is that they're looking at an autism diagnosis which may be instead of bipolar or as well as!

If it's instead of, it means he's been taking bipolar meds for years unnecessarily which is very distressing for him, and if it's as well as, it means he's got yet another condition. He showed me info on the particular form of autism they're looking at called PDA & it's pretty much a word profile of his entire life since a baby, so now he's revisiting everything through the "lens" of autism & causing himself great stress. For my other sons & I it makes it easier to understand a lot of things about him, but we regularly get it wrong when interacting as he's so intelligent we often expect him to understand certain everyday things, but of course he doesn't & we don't realise until too late.

I really need some help in working out how to respond without making things worse. It's been a terrible couple of days as it's coming up to my birthday tomorrow (also the date my husband died in 2002) & my son's been organising it for his brothers & seemed really proud of things. This week he's been getting worse & worse with anxieties though, which makes him really annoyed with me. Wants help but hates to ask, gets upset when I don't pick up on hints (very subtle hints!), hates relying on "his mummy" at age 37 but then gives me "another chance" to help......... He's just a mess at the moment & my brain's starting to just shut down when he phones or messages as I don't know what to do or how to help. He's starting to get very hopeless & told me he's nearly done. I found some info on autistic shutdowns this morning which describes what's happening perfectly, but I still don't know what sort of reponses or activity would help in the situation.

His psychiatrist has applied for him to get therapy sessions at the Centre for Clinical Interventions but there's a wait list, he's got physical pain & needs to see a neurosurgeon but there's a wait list so we're going private in August. It's like every thing we try has a waiting period so he's just sitting around his house doing nothing all day & getting more anxious. He can't even play much music which used to be his escape.

If anyone has some suggestions I would be really appreciative as it's making me more & more anxious & teary which isn't like me. I feel I've run out of coping skills.