Thanks Bryanna! You’ve got the gears in my head turning!IMO, it would help if he could work out a trip where he could use his US visa even if the US visit is for just a couple of days, maybe for work reasons or sightseeing/meet friends.
His trip itinerary could be: China >> Canada >> US >> China
He would also need to focus on proving he has strong ties to China (which he does) + include a Travel History explanation (scanned visas, previous entry/exit dates and purpose of each visit).
He is eligible to apply for CAN+ processing if his US visa is valid
Yes he is eligible for CAN+! He has a B1/B2 US visa valid until his passport expires. Thank goodness!