Hello @MumMumMum
Reading your post I'm struck with the amount of weight that you must be carrying while trying to support your family, and before touching on your son, I want to ask whether you have any supports in place? I can hear that your family relies on you heavily, who are you able to lean on when things feel overwhelming?
Caring for a loved one who is legally an adult, at least in regards to medical decisions, can be a huge challenge. We can't force others to accept treatment, even if we can see the benefit it would do them. The only times that adults can be forced into treatment is in cases where they are at immediate risk of significantly hurting themself or others. This can leave us feeling somewhat powerless in these situations.
Some actions you can take are to stay in the loop with his psychologist as much as you're able so that you can ensure that you are on the same page in his support, and this can hopefully also provide you with some guidance and strategies on how to best do this.
You can also enforce some boundaries around respectful behaviours in the home. Boundaries are very hard to set, and there will be pushback. It's helpful to remember that setting boundaries doesn't mean that you are able to control another's behaviour, but it sets a precedent on how you will respond, and when maintained consistently it will show that certain behaviours will not bring the response they're looking for from you.
Lastly, you can ensure that your son knows that you will be there to encourage and support his engagement in treatment the moment he is ready. This must be a very confusing and overwhelming time for him and sometimes it feels less frightening to stay in this space, rather than accepting help and making oneself vulnerable. It may just take time for him to feel ready.
Again, as much as you can I encourage you to take care of yourself and reach out for and accept help and support when you're able, and know that the forums community is here for you