It didn't ruin the pair of pants, just made them wet. They can be washed. If he were to owe her anything, it would be dry cleaning. It's unfortunate, though, because OP had to sit in wet, sticky, uncomfortable pants for 5 hours.

This FML is pretty damn funny if you accidentally read "dick" instead of "drink" like I did.

How the fuck does that have any relation to the FML? I am so fucking sick of seeing dumb ass comments on FMLs that have nothing to do with them. Some people shouldn't be allowed to comment.

They probably didn't notice until it was already starting to spill

It also could have been uncomfortable to tell someone what to do. I don't know if I would have said to someone I didn't know not to do something.