Seller's Insurance Claim Check Delayed and have to pay roofer

[Matthew Allen]

I am closing on a house next week. The seller and I agreed they would file a claim on the roof due to hail damage, and I would cover any out of pocket costs like deductibles, overage, etc. I arranged the roofer, the seller signed the contract, and they will wrap up the roof tomorrow. The roofer requires half at completion and half 7 days later for recoverable depreciation check to come in. The check came in last week from the insurance company, was sent to the lender to endorse, and they just put it in the mail Wednesday. It has not arrived yet. Long story short, the seller can't afford to pay for the roof and wait for the other. I can pay it, but I'm not entirely sure what I need to protect myself (POA, simple contract, etc?). Any ideas? Ideally I'd run this by an Atty, but time doesn't really allow for that.