According to the requirements, he would need to prove employment, assets, bank accounts, and all of these he has. He has an apartment, he has a job, he has a bank account all in Peru under his name. There would be no reason he would want to stay in Canada.
Not only that especially if on his application it shows that he is coming to get married, he would have every right to stay because I will be at the airport before him waiting outside immigration to ensure that if there is any question they can come out and ask me. I will be there and I can show them my Canadian citizenship, my SSI, my Canadian passport, etc. Once we are married, it really shouldn't make any difference, he would be protected by being married to a Canadian citizen, correct? and if I ask for a change in status...?