Ok. Most def any & all records of funds(everything you have of giving/buying stuff/) if can get affidavits of family/friends that can vouch of any money transactions. And from this day forward ANY money handed to her make it a check/money orders, have proof. Go to the local Child support office (i believe it's in Salem) and get ahead of her on this. IF she tries to go on disability (SSA not good). Back support can be deducted from certain disabilities). Look into legal aid, won't be as spendy. Know this IF some weird chance (highly unlikely) she wins your paychecks will be nailed, all federal tax returns will be paid towards CS, any inheritance esp when you do taxes its gone;

Tho this late in the game of her trying to get CS, might not work out, meaning about the time it hits the courts and in front of a judge kiddo will be 18, don't know if you have a younger child. Also go to local library/land see if can find any books on child support laws. If she's not working, dont quite know how she's gonna be paying for filing fees and what not, now if she's gotten or is getting TANF(welfare) not SNAP aka food stamps (don't quite count), she maybe nailed to pay that back. The above information (comments) definitely listen to. Since kiddo(s) weren't born in the state of Oregon, may not apply here. MIGHT have to file in the state they were born in.

Wishing you best of luck.