It wouldn't be the vacuum pump,as it isn't used for the brakes. It must be the PS pump that is acting up. If is affecting both PS and brakes,the pump is the common item between the two. I have never seen a pump just quit totally,they usually get weak,or the pressure is low
Try giving the pump a good whack. I had the a similar problem,in the middle of winter on a really cold day. Started the truck and the pump started moaning,then no PS or brake assist. Shut it off,smacked the pump a few times and all was good. I think the relief valve was stuck,maybe hers is too ?
One other thing to check is does she have vacuum for the heater controls ? If she doesn't then maybe whatever drives the PS and vacuum pump has sheared off ?
I'll dig up some prices for you