The original SKY digbox's were really bad "EMI" emitters - that forced me to replace all the old single-screened cables connected to mine (one of the very first of those) with half-decent double-screened stuff, and that "sorted" the "local" interference problem. Since then, all my cables have been double-screened stuff, and I haven't had any recent such issues..
TBH, and from my previous experience in the "professional world", if the owner of "that" TV replaced all his "local" cables with properly installed double-screened cables then he could almost certainly continue to use it without causing the reported interfernce to the local wireless broadband system - because those cables are the "transmitting antennae" for all that EMI from the TV (in the TV itself, the PCB/PWB tracks are almost always too short to be "efficient" emitters of EMI generated within it)