Valve Cover Condensation. Happens a lot. But it takes years of sitting. I don't have the patients, or should I say time left, to screw with that. I would buy another that WAS running now and check valve train and the oil while it was running. Too many motors out there to spend months on that. IMO.
Possibly not as bad as it looks. Possibly.
I'm sure the seller did not know it was that bad. If he is a good guy, he will give some or all money back. Unless you got it for cheap money.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn