My Mother adopted a boy, is he my brother or a non-mahram to me?

What your parents did in terms of helping him (Ramy) is commendable. However, the fact remains the same; he is not regarded as your mahram. This does not mean you are now discriminating against him. It just means that you cannot be alone with him. Your family should help him where they can but he cannot be regarded as your mahram.

Allah knows best