What happens if the buyer's loan falls through?

It depends on the contract. Texas contracts that depend on financing give the buyer a limited time to get approval, and if the loan isn't approved in that time, the buyer may be able to terminate and recover their earnest money. If the buyer doesn't use that right in time and then can't close, the seller may be entitled to the earnest money. In either case, the home can go back on the market. I reduce this risk by calling the lender to vet the buyer's financing before we accept. If I have any concerns, I raise them right away. Often a financing problem is only a matter of a few extra days, so flexibility between the agents and clients is key.