The rest most likely went for the interest and penalties for that years taxes.
If there are still taxes, penalties, and/or interest due for that year, yes.And can they still collect on 1998?
The Statute of Limitiations tolled (stopped ticking) when they collected the money.Since they applied money to that year, Does that reactivate that year for another 10 years?
As gigirle and Bubba J stated; he needs to contact them and see if he can work something out. It's not going to get better until then, it's only going to get worse.

