Hi Shine ~ welcome.
A lot of the threads on here concern people who simply cannot tell whether or not the other person is interested in them / likes them.
I suppose that this could be for a number of reasons ~ shyness; disapproving parents; not being interested but not wanting to say so for fear of upsetting the person; not being sure; having too many commitments; liking them but preferring someone else; being too far away; being too young for a relationship; etc; etc.
I don't know what the answer is ~ not in this case or the others, because the only person who really knows is the one making the decision.
In this case, though, there is someone who might be able to help ~ or maybe two people ~ your brother, and his girlfriend. Ask your brother for some genuine advice.
Good luck!