I'm also a huge empath so wanted him to lean on me
remember the theory about the circle of grief and bereavement.
basically, the person in the centre of the circle, who is the most affected, gets to choose what they need and when they need it.
as the circle widens outwards, there are others also affected by the situation, so family, wider relatives, friends.
unfortunately, painful though it is, you are probably on the outmost edge of the circle, because you have only know him for a few weeks,
if he has decided to finish the relationship either completely or while he is going through his father's illness, supporting him, supporting his family, as it could be that his father's life is coming to an end, then you'll need to reconcile it as what he needs and respect the choice he has made.
hopefully you have good friends or family you can share your own sadness with, due to the loss of this new relationship that wasn't to be. If he does come back later, you'll need to be sure he is serious as you wouldn't want it to become a pattern where he abandons you whenever there's a crisis.