[Principled]

At 40 hrs, he probably wouldn’t get healthcare and the company may not be willing to increase his hours.

On what do you base your conjecture that "at 40 hours he wouldn't get healthcare"??

If he gets healthcare at 36 hours, why not at 40?

[NewHampshireDuo]

Only conjecture but if full time is redefined as 40, he would no longer be a full time employee and the company might not increase his hours.