Hi Swan. Sorry, have only just seen this post, otherwise I'd have responded earlier.
Hmm. Having done exactly what you're considering with my DS1 (also with ASD, as you know), I can see pros and cons.
DS1 made the decision easy for me, in a way, by not coping with school, so I had to take him out. I'm sure that, if he'd been happy at school, I would never have taken the path of home education. I really was thrown into it. Once we'd taken the plunge, we had a contrast between the misery and stress of school and the happiness and relaxation of home ed, which made it clear it was the right decision. However, DS1 has poor concentration, which made teaching him hard work, and the novelty of being home educated wore off for him after a while. And his social anxiety meant mixing with home ed groups was painful for him, so he ended up with no friends at all. Would your DS2 be able to keep in touch with anyone at school (although I see he doesn't have any/many friends) or have you thought of how he might make new friends?
Your wish for your DS to 'take ownership' of his own work might work in a home ed setting, but you may find that it would continue to be frustrating for you and him. My DS never takes ownership of any set work and always has to be cajoled, reminded, helped, etc. It is maddening and exhausting. I'm actually very happy when he doesn't get any homework from the LA online schooling service because it lets me off the hook. It always feels like homework for me, not him.
On the other hand, it is wonderful to be able to see exactly where your DC needs support and be able to concentrate on that, eg. in your son's case his literacy skills. Now I have DS2 at home, he practises his handwriting every day. (It is atrocious!
He rarely leaves spaces between words and won't join up the letters. And still reverses his 'z's
). I asked him how often he had handwriting lessons at school and he said once a week. Now he does it every morning, quite willingly, and it is, very slowly, improving.
I also enjoy being in control of how he learns. For example, we use Galore Park text books for English and they are excellent and so much more thorough and interesting than the way he was taught at school. For instance, spelling is taught in the context of a passage read or as a word search, instead of with a list of random spellings to learn, as at DS2's school.
He has a school friend round to play this morning and I heard them discussing DS2's home ed. DS2 said that he enjoyed it more than school because he understood things better and because if he didn't I took the time to explain it patiently. That was good to hear - and showed up a definite advantage to home ed, ie. you can teach your child at his pace and in the way that suits him.
Saracen makes a good point that this is a good time for your son to try home ed, as he can always return later. Maybe that would give him a break from the stress of school (and you, as you are clearly exhausted with supporting him) and it would give you a chance to find out what home ed is like, as it's clearly been on your mind for a while.
How would your other children cope with DS2 being home educated? The classic consequence of home educating one child is that the others follow suit .
My own pathway to home ed started with the niggling feelings you are describing, so I do understand. Maybe those niggles are your instincts that something isn't right for DS2 in the school setting and that you could do better at home. It might be worth a try.