Aging parents + parent plus loans

My in-laws are struggling to make payments on parent plus loans, and the child whom they benefitted is not in a position to help. I think I found a way out?? Here are the numbers:

• Total current balance: $155,206 at 8.25%
• Enrolled in ICR
• Monthly payments around $500
• Halfway to achieving PSLF forgiveness, then MIL lost job (not likely she will re-enter the workforce, although she has submitted many applications)
• MIL current income: $0 (will begin receiving SSI in February: $24,060/yr)
• FIL current income (social security): $30k/year

My questions are:

• Since the loans are in MIL's name, can they do 2025 taxes as married/filing separately in order to exclude FIL's income from calculations? I believe this would bring monthly payments down to $0
• I hear ICR is going away… should they enroll in IBR asap?
• Any other strategies we should consider?