@ ChrisBP747:
I'm genuinely glad your grandfather was lucky in this regard. His membership in the Wehrmacht the Heer, I assume; so, a soldier on the ground may have saved him from the brunt of Soviet hospitality
but that may have been more closely related to where and when he fought than to whether he was Wehrmacht or a species of SS.
In some cases, however, Soviet leadership made little distinction between regular armed forces and Waffen-SS, nor in their treatment.
One example my “favourite”; I love ragging on the many hells of Stalingrad but I'll keep this one short is in how the Wehrmacht, alongside the Waffen SS and backed with a motley crew of NSDAP misfits some of them relegated to the "himmelfahrtskommando" because, Ha Ha’ which included members of the SS-TV who (a) requested a transfer while of questionable loyalty or (b) violated rules governing the behaviour of guards either through a collection of minor transgressions or for a more significant one that nonetheless didn't warrant immediate execution.
And as many were marked with bloodgroup tattoos,
early Waffen SS as well as SS-TV (who, though best known for running concentration camps, were capable of being called to active service).
Yes, the Soviets had a special hatred for the SS. That didn’t stop them from sharing their tender mercies with all their other captives:
The Soviets took about 110 000 prisoners after the Battle for Stalingrad ended.
5000 returned, almost all of them long years after the war was done.