EEEP! No wonder he's having problems! First of all, the average bowl needs to be cleaned every two days to keep toxic waste at a safe level.
Secondly, I'd say the average room temp in vancouver is about 65-68. A betta needs water of 74 at the very least, 80 is optimal. The cold water drastically decreases their lifespan.
You might be able to save him if you purchase a tank of 2 gallons or more with a heater, but if he has been doing this for a month and has been living his whole life in such conditions you may not be able to bring him back from the edge.
In any case, here is a good care sheet to read: http://www.tropicalfishkeeping.com/b...are-faq-20058/