Since you've already sent him a note and talked to the landlord about this, it's been an ongoing issue, and you seem to be determined to get results, you may need to consider legal action.
I'm not sure what real estate law is like in bc, but there is a general legal principle of "quiet enjoyment" in real estate law. That is, that you have a right to prevent others from infringing on conditions necessary to your enjoying your legal place of residence.
You may want to talk to your other neighbors and see if it is an issue for them too. Then talk to a real estate lawyer (a legal clinic would be cheaper if you are eligible). In principle there might be a book on real estate law or other free/low cost info on the subject.
If in fact you have a legal right to quiet enjoyment (I'm guessing that you probably do), you may be able to send a letter (via a traceable method so it serves as formal legal notice) to the landlord (along with other tenants if they feel the same) demanding that the issue has to be resolved or that you will stop paying rent (along with your neighbors, if they want to do this).
There may have to be some legally defined period of advanced notice, but this is a typical method forcing landlords to do stuff when they drag their feet on something.
The landlord in turn would basically be forced to tell this guy that he has to clean up or face eviction proceedings.