Cashing a cheque for someone else in my name?

I have a boyfriend who works with a work visa and has cashed many checks from his boss before. His boss as far as I know does not take taxes.....and now my boyfriend wants his next check a whopping $15,000 to go in MY name so I can cash it for him. Is this legal, even though I havent worked and I can say its my work check and willing to pay the taxes on it , and willing to pay the taxes on it at the end of the year ... or claim it as a personal loan?? I`m just curiouose the idea of tha man signing a check to me doesnt seem wrong, but tis for the ammount that scares me......ANY inof would be greatly appreciated. Miss Nina, posted something along these lines and I tried to e-mial her for advice but lost her in this confusion of trying to make an account etc. Thank yo all for your words of advice......not sure if it mattters but I am located in Canada.