I am sorry you have to experience that. Unfortunately a lot of people still don't understand that homosexuality does not make you lesser. It is still a stereotype that many people haven't overcome.
What would happen if you spoke to him calmly about his view? Question the accuracy of what he is saying and doing? I know that sometimes people don't realise how offensive they are being until called up on it. Unfortunately there are those who do know though and don't care.
I am sorry you are having to struggle through this on your own - is there anyone you can talk to? A friend, counsellor or someone else you are close to? You shouldn't have to go through this alone.
Also I would suggest having a look online for different articles and resources about telling family. It shouldn't happen but unfortunately this kind of issue is far too common