The man was lying on the kitchen floor in a motel when a liquid accelerant was poured on him and then lit on fire, police said. The incident was filmed.
Matthew Sweet-Grant, 20, and Joshua McWhirter, 18, have been charged with aggravated assault.
The victim is still in hospital with "very serious injuries," said Kelowna RCMP Const. Kris Clark.
"It's certainly very disturbing that somebody might do this to somebody that's incapacitated by drugs or alcohol. They're defenceless," Clark said.
"But if you do a quick search on the internet you can certainly see this isn't the first time that it's happened and it probably won't be the last."
Clarke said investigators believe one of the suspects may have done something similar before, and RCMP are asking anyone with information about previous incidents to come forward.