The fact he is on the birth certificate grants no automatic forgiveness for an overstay; marriage to a US citizen is required. However, the 2 year home residency must also have a waiver. If it is not, he will be required to serve it in his home country. Once he leaves, he will be banned for 10 years without another type of waiver.

A hardship on him and needing to work are no reasons for him to be granted a waiver.

Three children is rather late to be worrying about not wanting to marry. Is there some reason that this is not possible?

Since he has an attorney, he needs to be cooperating with him/her.