Regardless what the seller may ask, what is the amount you can a

If you can afford the current offer plus the repair cost, just buy as is and fix at your own expense.

If the 8 thousand makes the difference.... well, you have to negotiate with seller. I would suggest asking for 5k for the AC, because it is indeed in need of replacement. Other small issues take care it yourself.

We are selling a house and got multiple offers. The highest offer drew a long list of this and that. We immediately reject it and passed to the next highest offer. So be realistic.