Jermaine Jackson -- Defies MJ's Policy ... Kids Need Their Mom

Michael Jackson is rolling in his grave -- because brother Jermaine Jackson is now encouraging MJ's daughter to spend time with her birth mom.

MJ famously never wanted his kids Prince and Paris to have a relationship with their biological mother Debbie Rowe -- cutting off all contact between Debbie and the children after their divorce in 1999. Debbie gave away all custody rights in 2001.

But Jermaine has reversed Michael's policy -- telling TMZ, it's great that Paris is getting to know her mom.