If they're returning to school to play hockey, they're doing it for the wrong reason.
Get your degree and get on with your life.
I don't think the life decisions of 24-year-old strangers is any of our business, nor should we assign some sort of conditions on who does what, and when.
If a player has their degree, and has eligibility left, and wants to come back to take three random courses and play competitive hockey for one more year before they're forced to give it up forever, who the hell are we to judge? This happened before the pandemic, for lots of reasons: taking some extra courses to make their resume more appealing, looking forward to grad school, or, yes, just to play again.
If you meet the eligibility requirements and pass your classes, it's not our business to put forth any further stipulations than that.