How much would y’all pay 2 guys to replace a 40 gal hot water heater in the attic?

Asking this sub specifically because of the heat..

My bil (and his friend) replaced my water heater, which is in the attic. I already paid for the water heater, but when asked how much I owe for labor he just said "I don't know". I've always paid him very well, but this is definitely the biggest job he's done. Also, it took them about 3 hours.

So, how much should I pay 2 guys to take the old one out of the attic, dispose of it, then haul the new one up into the attic and connect it?

Edit: I'm also having ac problems, so they "blew out the pan" while they were up there.