I'm going to dump my bf while his dad is sick
Could you explain to me why you want to be so cruel?
Because he needs to spend time with his mom and dad. He needs them more than he needs me right now.
It seems like now would be the time that he really needs you. You should not break up with them at a time when they need you the most.
I'm in the way of him spending time with his dad.
If you think he's spending too much time with you when his dad is sick, tell him. Help him see that it is these times when family needs to be together the most.