I'll agree with the loan for the tires. Maybe put the repayment in the settlement. That way, the pressing problem will have been taken care of while holding her responsible for it.
But the kids need to be safe.
When my W busted out the radiator in her car a couple of weeks ago; it just sat at the repair shop until she had the money. She borrowed her Gfather's truck until she could fix "my" car. In the settlement, I get it back; cause it's in my name and not paid for.