I would suit them down for a conversation about it, explaining that you DO want the money back but that you'll give them some grace for say 6 months, at which point you'll be sitting them down again for a discussion regarding resuming repayments which may mean reinstating payments, be they back to what they were originally or at a reduced rate for another stated timescale.
I would say, family or not, if ever anyone gets into a situation of lending money you should put something in writing, stating the amount lent, timescales for repayment. You can always add subsequent changes into the written document. In addition, keep written (signed) records of all payments to keep everyone informed of the ongoing situation.
A written document, even handwritten, signed by both/all parties allows everyone to know what's been done and what the rules are. Even if you never think things will get to the point of going to court to enforce repayment, especially with family and friends, situations can change, you might have an emergency yourself where the funds are needed and your only answer is to go to court to get your money back, if this ever happened you'd need documentary evidence of the loan agreement and payments made so far, without it it's highly likely that the courts wouldn't do anything to help and even tell you it's not enforceable and the person owing the money could legitimately/legally walk away and never pay you another penny!