What I ended up doing - I set her laptop with a static IP and added TCP and UDP routes for port 53 (the one used for DNS queries) to 8.8.8.8 - no complaints since ;) I use a cheap Mikrotik router between my ISP one and the actual network (well, a NAS and a Unifi AP, the rest is wireless) so doing it was easy ;)
Heh, back in my call centre days we used this neat little app called Caffeine. No installation required, just double click and stay online for the whole shift.