96 ford windstar broken rear lugnut stud?

Rear drum seized up so removed tire tapped with hammer and sprayed wd40 and it spins again, but one of the studs snapped off and is stuck inside of the lugnut so is it still safe to drive with 4 lugnuts holding tire on instead of 5 as its the rear tire and am guess its less stress on the rear tire lugnuts then the front tires.

It wouldn't bother me. If there's enough room you can drive the broken stud out and pull in a new one with a new lug nut. And some tapping.

Honestly yes it will be fine 99.999% of the time I have, and no many people that have driven thousands of miles and no problems, never heard of anyone having a problem but it is a easy cheap fix. My local used tire shop charges 10 bucks to fix.

Buy a new one one at any auto parts store.

You can replace the stud without removing the axle. Most any garage can do that.