I'm really sorry about your Grandmother and Mum. No wonder you are struggling. Two big losses in a very short space of time would floor most people in normal circumstances, but with the added stress of your ds, the pandemic and the strange way of life in general, it must be really hard. 
What is happening with your ds education now? He should be given some alternative if he's been permanently excluded, or have a return date if he's going back to his usual school?
He is unable to communicate with you, but his behaviour is showing you that there is something wrong. Is there stuff going on in his life that he is overwhelmed by? Struggling with lessons in school? In with 'the wrong crowd'?
In my area, we have youth mentors, accessed via school...they are usually brilliant at finding out the issues, raising self esteem a bit and building good relationships with young people. Is there anything like that available? Most councils have a behaviour support department that schools can access...if school isn't helping, can you go to them directly?
I don't think I would send him to his Dads. I think like pp's have said, he will see that as being pushed away.
I think that he is probably hurting, but just can't find the words to tell you, or doesn't know what's wrong, but isn't able to say it, and so is showing it by acting out.
Then you react, he kicks off, and the cycle continues.
Is there a common ground you can find? Watching a tv programme together...even if it's awful and his choice! Asking him to play you his favourite tune at the moment and faking interest in it? Going for a McDonald's drive through together and talking rubbish about nothing, but being equals rather than parent/child if that makes sense. If it goes well, you tell him how much you enjoyed being with him, and thank him for coming.
Anything that involves you 'bonding' and breaking the cycle for a while, and allowing you to be with him in non conflict for a while.
It's so very hard, and I wish you all the luck... x