The brake aspect of this is puzzling.
Concours, did your sister notice the brake problem before the dealer "serviced" (I won't say "fixed") the wheel? I would understand if she didn't given the excitement of riding the bike with the wheel trying to go to pieces. There must be air in there - maybe they did some bozo move when the wheel was off - what's the brake fluid level look like?
The only time I've had spokes loosen is on dirt bikes. I've had many street bikes with wire spoke wheels also, but none of the street bikes were new when I got them.