I am so sorry about your dad. But it is sad how much influence our parents have on us no matter how old we get. On one hand we do not want to disappoint them and the other we know we have to live our own life. Now is that love or respect or just pounded into our head since an early age. I think you are giving a lot to help out , especially being pregnant and living so far away.
When I read the part about your brother thinking that he is the only one that can take care of your dad and he knows best etc etc. I laughed! I have very close friends who were in the same situation. I dont know if your brother is older and that may have something to do with it. But the primary care givers seem to take over. And then it is their way or the highway!
You may not have had a great relationship with your dad. And you may not be close friends as well as father and daughter. But do not let anyone make you think he loves you less. I know I do not get along with my mom. She does not really like me..but the love is still there! So do not let anyone fool you about that.