Michael Lohan's lawyer, John DiMascio, said he plans to file a motion to set aside the agreement and impending divorce by proving Dina Lohan did not live up to the terms. Dina Lohan accused Michael of breaking the rules first, but did not specify how.
The two also are arguing in Nassau Family Court whether Michael Lohan has the right to visit their younger children.
They have three other children in addition to Lindsay: Michael, 19; Ali, 13; and Dakota, 10.
Photos: Lindsay's Crash
Lindsay, who turns 21 next month, checked into rehab after a wild Memorial Day weekend during which she crashed her Mercedes-Benz into a curb.
She was arrested on suspicion of driving under the influence and was photographed slumped in the passenger seat of a friend's car.
Michael Lohan was released from prison in March after serving nearly two years for attempted assault and driving while intoxicated.