Is it allowable to accept a gift from a Muslim who is involved in corruption and bribery?

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 certain that your relative got this particular gift from corruption or similar illicit sources, then it is not lawful for you to accept it from him. If you do not know the source of this gift, and if that relative has other lawful income that is mixed with his illicit earnings, then it is dislikeable for you to accept a gift from him.

On the other hand, exhort this relative, advise him, and try to convince him to follow the right path.

Allah knows best.