I'm sorry for your family situation with both Mr @Shaz51 being upset by things they said (and not wanting xmas with them) and by their lack of support/visting you. And you already have such a heavy load with health too. *big caring hugs*
I hope your cousins and family make an effort to visit you, even if you cannot go out to them on xmas due to Mr Shaz.
I was thinking about what you said re: ASD diagnosis and his processing it.
What does a diagnosis change for *him*? In his eyes and emotions. How does he *interpret* meaning behind it?
I wonder if there could be a way to reframe the diagnosis as a sign of how strong he has been all his life? To have been high functioning *despite* living in a world designed for neurotypical people and him having to adapt/mask/etc to "fit" the mould and the extra stress that it brings?
Perhaps a relief that his MH is not his "fault" but could be significantly impacted/exacerbated (or less responsive to traditional treatments) due to ASD neurodiversity factors?
Have to start work now, but was thinking about it whilst i got ready for work and wanted to ensure to pass along my musings just in case they help.
Either way - ypu have my support and care and friendly love.