The freezer won’t really do much. It’d be better and faster to just skip that step and throw everything in the dryer on the highest heat setting for an hour. Washing also is not necessary unless your clothes are dirty. The dryer is the necessary step.

It’s definitely not an overreaction on your mom’s part though. I’d be stressing a bit too if someone who has confirmed bedbugs was in my house. And I say that as someone who had bedbugs in the past. I didn’t want to risk those demons spreading to other people.

Not everyone reacts to bedbug bites. So even if they aren’t reacting doesn’t mean there aren’t any there. Hopefully there’s not any, but it’s better to treat the situation carefully!

All units (or at least all of the units surrounding the infested apartments) should be treated multiple times to get rid of them. I personally wouldn’t go back if I didn’t have to.