He might just as well take care of it in one appointment.
As a buyer, who maybe buys a property only once and thus makes the biggest investment of their life, do you know what will be in a purchase contract and what questions need to be asked about it?
With all due respect, they are complete laymen. For self-protection, I wouldn’t just sign a contract like that without being able to calmly consider the document, my questions, and the consequences of the agreements.
A purchase contract for a property, which you approach with as little preparation time as a doorstep sale (which at least still includes a right of withdrawal), cannot simply be signed on the spot.