Many years of back taxes

What is the name of your state? New Jersey

My son-in-law hasn't filed taxes since 1988. The IRS caught up with him and are now taking 70% of is paycheck each week. All those years he worked and paid taxes, just didn't file. Now he's trying to catch up and set things strait. He was married in '89-'93 and his ex worked part of that time too but didn't file. He wants to file a joint return but she refuses to sign her name for fear of being held responsible for those years. He had custody of their 2 children during that time so he's able to take them as deductions but if he has to file married filing single he'll really get crunched. Is there any law that obligates her to sign the joint return?

Thanks!!

He should consult a tax attorney immediately. The IRS has certain statutes of limitation that prevent them from collecting taxes from too far back. It could be that the IRS is "collecting" taxes that can't legally be imposed. If the statute of limitations expired, he could file an offer in compromise of $100 for the expired taxes & the IRS would probably take it.

SOL

From ALL advise I have been given by an enrolled agent and a tax attorney; There is no SOL on unfiled tax returns.