How or can I find out if my brother is my true brother,but the problem is he died last year.Is there a way round this?

How did you find this out. Is this person who told you a reliable source.

What does "true brother" mean/ according to you/?
He can or cannot be biologically related to you but he can still be your legal brother in the eyes of the law.

If he is legally your brother, then he is your real brother.

Same mother and father ? Or 1/2 brother,
What is it, you are wanting to try and find out.