I was at a table with a complete maniac who was drunk/on tilt. He was open raising as much as $55 at $1/3.

Anyway, some players started to leave this table as it was the feeder game to 2 other tables. But it got down to 3 handed, and everyone was saying "ok how bout we play one more hand". Just because I'm a complete live noob, I asked if we had to have more than 3 to keep playing, and the dealer said you can even play HU if you want.

Well, the maniac had just re-bought to $400, and he went to take a smoke break.

I was thinking about trying to get him to play heads up or maybe 3 handed, but I figured california drop rake would be pretty much unbeatable HU.

Does this hold true versus a player like this?

no. play him now. ive been in ur shoes b4 and played the fish at 2/5 as he was sitting with 100bbs and by the time i busted him i took him for like $400 after having lost a hundred in rake :/

but this question should also probably be posted in a different forum fwiw.

You may lose a decent amount to the rake but you can definitely beat it. In a live HU cash game its all about out lasting your opponent. Get a game plan and stick to it. Don't get out of line and stay aggressive. As long as you have found a drooler with money you might as well play him HU. Be patient and play your A game especially against a maniac.

Ddunno how much $/pot we are talking here exactly but you can defo beat any half-reasonable rake from a guy betting 55$ into 4$ pot.
But don't do it if you don't have at least 10 BIs with you as this game will be rocky