It sounds like you are in a really difficult situation with your special needs child dependent on you. Like you say – change will come anyway and being (to some extent) in control of the change is better than uncontrolled change. I really would advise you to find some counselling about this – perhaps some form of family therapy as I feel there are a lot of dynamics at play.
If you are in the UK – it might be worth talking to the Gordon Moody Association to see if a residential with them would be possible – but I get a sense you are not a UK citizen.
All we can do is give you support – but it feels to me that you need a more practical intervention closer to home. I hope you can find the wherewithall to speak to someone and move forwards. I wish you well.