I'm really sorry to hear what you've been through!
You won't get any help from the school, but you might get some from the LA. If you don't really want to be home educating but have been pushed into it, it would be worth complaining to the LA about the school's behaviour. Encouraging families to home educate when they don't want to is known as "off-rolling" and schools shouldn't be doing it.
Are there other local schools you would consider? Another option is college. Some colleges offer full-time or part-time education for 14-16 year olds, and some kids say that the atmosphere there can be better than school. Contact your local colleges to see what's available. If he is going to do school again, it would be good to aim to get him in somewhere at the start of Y10, as the school system is so inflexible that it's hard to join after that time. Sitting exams as an independent candidate is doable but requires some effort to organise and there are costs involved.
That isn't meant to discourage you from home educating if you feel it's best for your son. Even if he ends up at college or another school, a break should help him recover from the stress, so maybe he'd like to have the rest of the year at home anyhow.
I can't help with the educational resources, as one of my kids did informal learning instead, and the other isn't at that academic stage and might do likewise. I'm sure other people will be along soon to help with that.
The best way to make contact with local home educators is via Facebook. For example, I used the Facebook search bar to search for "Sunderland home education" and found several groups you might like to join. They will be able to help you with suggestions on local activities, places to visit, exam centres and so on as well as support.
Good luck!! I hope your son will be feeling more relaxed soon.