All perfect praise be to AllahThe Lord of The Worlds and may His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions.
This person must return to the fold of Islam by uttering the two testimonies of faith and making repentance to Allah from all acts that lead to disbelief. Also, he must make a new marriage contract because the old one was dissolved after he had committed this act of disbelief. Moreover, since there is no waiting period for his wife, then she is in state of Talaq ba`en baynona Soghra (Minor irrevocable divorce); consequently, she can get back to him only by a new marriage contract. And Allah The Almighty Knows Best.