If the parents join MS-13, then can they stay?
Not only could they stay but they'd be eligible to get a loan to buy a house as well.
P.S. Keep you eyes and ears open for stories about pregnant muslim women being brought into the U.S. on tourist visas (Detroit and Toledo areas specifically) to give birth to their children who are automatically made U.S. citizens even though their mothers are only here on visas.
The mothers and children then return to the middle east complete with a U.S. passport allowing the child to come back once he's been trained to be a good jihadist.
The muslims have a very long range plan with respect to the conquest of the U.S.