If my sister believes in God and Jesus is that enough so she can enter Heaven? She doesnt like how the Bible doesnt like gay people.
Believing is one thing, but acting on the belief is more better. Anyone can believe in something. But acting upon something shows more faith and dedication. I would suggest that you ask your sister to repent. Ask for forgiveness, and accept Jesus as her Lord and saviour. Because the time is short. Only god can save, and if you want your sister to be saved? then the step has to come from her.
Who is the Pope to make claims like this? He will be going against God. And anyone who is against God? well sorry to say, but he/she is an anitichrist. and you know were any denial of God comes from.