If you are outside of Canada then your PR status is gone. You will have to apply for PR again from the start. If you don't qualify to apply at this time, then you will have to wait until you do before you can apply again.
I am sure for all these years, you have been working and making your ends meet. If you have a good job, please my advise is stay there and enjoy life. Here you have to past through a lot of things, so good enough you went back home.
Even if you have to re apply you may no qualify under the new rules.
If you are outside of Canada then your PR status is gone. You will have to apply for PR again from the start. If you don't qualify to apply at this time, then you will have to wait until you do before you can apply again.
He will have to somehow get rid of his current PR status before he could reapply.
So, either
a) he should apply for a PRTD and be declined, then fail to appeal (on the basis that he has almost 0% chance of winning), or
b) make his way to a land crossing via the USA, somehow, and expect to be reported. Then again fail to appeal.
Of course, if by some miracle, he gets in via a land crossing without being reported, then he is still a PR and must stay for at least 731 days in Canada before applying to renew. (Chances of this happening are almost nil).
This all presumes that he is not visa-exempt. If he can sneak in as a visa-exempt "visitor", then the miracle has happened.
I don't think this has any chance of working. If he was from a visa exempt country - then there would certainly be a chance. However since he's from a non-visa exempt country and his PR card has also expired, I think there's extremely little chance he can successfully enter Canada from the US. He should expect to be denied entry.
