The options are quite varied and really depend on the situation that your friend is in.
If he has a degree or acreditation from a university/college he MAY qualify for sponsorship of a work visa. He would have to find a company willing to hire and sponsor him, and that company would have to get a LMO (labour market opinion) to determine if he is the only qualified person for the position. The position generally has to be quite skilled.
He could apply to a university or college and stay on a student visa. This of course involves going to school, and paying international student fees and so can be quite expensive.
If he is qualified, he could apply for permanent residence to Canada; however, this process can take years, and I think you generally have to wait outside the country.
If he just has more traveling around and sight-seeing to do, he could leave the country, and come back as a tourist, but he would not be able to work. And crossing the border back into Canada he would have to be very careful with how he approached the situation, as in, he's not LIVING in Canada, he is there as a tourist, not to work, and he intends to leave after such-and-such a date. He should be able to show significant ties to his own country to convince the border guards that he plans to leave. If they believe this, he'd generally be authorized to stay for 6 months, however, they can restrict this to a shorter time if they want (and given that he's already spent a lot of time in Canada, they might say, alright we'll give you a month to finish off your sightseeing and then you have to leave). I think it would be difficult to convince the border officials that he's not playing to work illegally or overstay, given that he's already been in Canada long enough to set up roots. The more ties you have to Canada, the more difficult it is to convince them you plan to leave when your stay is up. He could find himself blocked from entering, and subject to an exclusion order (excluded from Canada usually for a period of 2 years but can be more or less)
Basically, immigration considers the length of the
Working Holiday Visa long enough to see the country, do some traveling, etc. If someone wishes to stay longer, they need to then become a contributing member of society, by immigrating or getting a legitimate working visa of some sort, or becoming a student. Without more information, it's really difficult to say whether there are any visas/options which would apply to your friend.
I'd suggest you read a lot of the information of the Goverment of Canada immigration website, and check out the forums at RoadToCanada.com if you have more questions.
Good luck!