Margiknot, I think you have come to the right place to begin with. Everyone has different ways of coping with health 'knock backs'. I think you should be quietly researching care for the future, and not necessarily involving your DH. If he says anything about it, say that you find it calming to do this research, and you won't be making any decisions yet.
You definitely need some specialist advice about future care for your son. Is there anyone involved in his care that you can ask? Even if you have little contact with adult social care, they have a duty of care to your son, and as NotSpaghetti says, will be able to discuss this with you.
I would also suggest looking at specialist charities and think about what is available. You can gather the information slowly and consider these ideas.
You can also slowly, start to look at 'future homes'. We are so lucky to have the Internet to help us with this. DH and I spent 5 years gathering information and looking at plots whilst thinking about building our house.
I hope that doing this will give you some useful thoughts, whilst not causing too much anxiety to your DH who may be quite unable to cope with them at the moment.
You also need to consider your health, but at least internet research needn't be too taxing.
I hope this helps.