Netflix through X1 interface under a third party internet provider

My mother lives in an assisted living facility that provides wireless internet. She has Xfinity cable TV and we'd like to get Netflix working through her X1 interface, but the cable box's workflow seems to require Xfinity internet. Is it possible for her to use Netflix through her cable box's interface with her current internet instead of Xfinity internet? The TV has its own Netflix workflow, but mom probably can't handle the complexity of toggling back and forth.