Well, laundry got done, but I came down with a massive headache which I have been sleeping off, but thank goodness, feeling much better now.
SQ - to answer your query in more detail: Your friend's status as a PR is safe even if he leaves the marriage, as long as the wife does not decide to get him in a jam by reporting him to CIC for a fraudulent marriage. If she did, there is a slim possibility he could be investigated, but if that is the case, she would have to show proof why the marriage is not genuine (the burden of proof is on her, not CIC), and he would have the opportunity to give his side of the story.
Most of the time, though, unless the sponsor is willing to vigorously pursue the matter and show proof of things such as another relationship, immediate abandonment of the marriage by the PR on arrival or shortly thereafter, and so on, CIC will do nothing more than take down the report and file it away somewhere. They simply do not have the manpower to go investigating every case of "he said, she said" when it comes to sponsored spouses. Where they might get active again is if he tries to sponsor another spouse. Currently they have cut down that by instituting the 5 year ban, so even if he left her and found someone else that he would have to sponsor, it would be another four years (you said he has been in Canada for a year now) before he could do so.
I am sorry for your friend's troubles, it seems his wife married a reputation (albeit deserved, it is not the majority's reputation!) rather than the man. I do believe that is very sad. She remains responsible for his basic financial well-being as per the sponsorship agreement, but tell him not to lean on that. That is between her and the government if she decides not to fulfill it. He should do his best to avoid any situation where he has to go on welfare, but if it is not possible, then he must do what he has to in order to survive.
If he is looking to become a citizen, that will not be impacted either. A sponsor can do nothing to help or hinder that process, it is purely administrative. He needs to prove residency for 1,095 days out of the past 4 years, take the test and pass it, that is what qualifies him, not her sponsorship.
