No, if that's her case where she has no physical access to the router, then she'll just have to make do with plugging it into her laptop's USB and plugging a handset into the RJ11. Plugging in a handset will definitely be less hassle for her than trying to set up the laptop's mic and speakers.
But yes, I think they require a valid CC# to set up the account, regardless of whether or not you purchased it without one.
magic jack comes with 1 year of service included, when setting up I was not required to enter any type of payment info. Just plug it in, it might ask you what type of headset you want to use I.E. phone.(assuming your parents have setup number etc).