My brother gave me present that I suspect it is coming from Haram earning? And I want to help him to become pious. Shall I accept his present or not? What can I do?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. If you are absolutely certain that the gift is of Haram sources then you are not allowed to accept it. If you are in doubt, then you ask the person and act according to the information he gives you. However, if you refuse the gift and do not want to accept it, you should do that in a wise and soft way. Allah knows best.