The agreement sounds right, as long as your friend is well aware of the potential for you to drop the lot against the wild Scandies.
He obviously thinks you're a +EV bet, and he's willing to risk his money to take that bet. If you're playing at all scared with his money though, then it won't work imo. You have to be willing to stick it in ahead knowing that without the absolute stone-cold nuts you do have a chance to lose the lot very quickly (especially if someone one-outers you on the river for a royal flush to beat your turned straight flush

) . I'm sure he wants you to play your A-game, and just clarify with him that he's happy to lose the lot.