+1. I'm not getting a great vibe about this; did he tell you he was an illegal immigrant when you met? Or at least before you started living together?kettle said:You will be financially responsible for your boyfriend for three years after he lands as a permanent resident.
Sponsoring is designed for common-law partners who live in a marriage like relationship. Referring to your partner as a boyfriend vs a spouse or partner does not bode well for the application or process.
Do you feel like you could marry this man right now? Do you consider him your husband? If so, then it will likely be worth it to you to sponsor him. If he is pressuring you to do something you are uncertain about, my advice would be do not undertake sponsorship.
The fact that he has been working here illegally isn't sitting well with me, but I know people can and have been approved despite overstaying. It could be a whole mess of trouble as he will have to provide work history and addresses for the past ten years.
Given that you say you have been living together for a year now, you did of course declare that on your income tax returns?
(CIC & CRA are now cross-referencing... )