The brothers and their other siblings were raised as Jehovah's Witnesses, but Jermaine, one of the original members of the Jackson 5, converted to Islam in 1989.
He told al-Arabiya TV Wednesday that Michael had read up on Islam and been moved by its teachings when he spent a year living in the Bahrain region.
Jermaine also said he encouraged Michael to convert because he felt it might help the reclusive star deal with his personal, legal and professional troubles.
"I believe that Islam would have helped him a lot. Had he converted, he would have been spared all the problems he had been subjected to throughout his life," Jermaine told al-Arabiya TV.