PR is different. Someone without status in the US can apply to immigrate. Provided they are 100% honest about their immigration history - approval is entirely feasible. However there are some complications. First of all, the file will be processed through the visa office in their home country and not through a US office. This means that if an interview is required (often there's no interview), it will be held in the applicant's home country and the applicant will have to attend in person. Also, I don't know if work experience gained illegally can be counted as experience in a Canadian immigration program (maybe it can?). Lastly, this person should be aware that once they leave the US they will be automatically banned from the country for 10 years and won't be able to re-enter under any circumstances for a full decade (even if it's just transiting through a US airport).