((((((((((((((Tempy)))))))))))))))
Regardless of the fact that you don't have a close relationship with your father, in my opinion, you should still go and be with your mother. She may be closer to your father than you are, so of course it will be harder on her than it is for you. She probably just wants someone to discuss things with and you being her child, it's only natural for her to turn to you in times of need...just like it's natural that a child would turn to their mother.
As far as having the "right" emotions go, there is no appropriate reaction actually written down somewhere. Everyone has different reactions to different events.
When I was at my great-grandads funeral, my cousin the same age as me was crying, and I didn't feel any sadness at all. So don't worry that you are "reacting wrong", because you aren't. You are just expressing your response to the event in your own way, which everyone has a right to do.
P.S = I'm sorry that your father is in a coma. I've never had any family members in that situation so I don't know what it's like, but I imagine that it would be pretty horrible.
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I = Vegan!
Animals = Friends.