Cutting the president’s video/audio was probably a system they were researching with Trump. It was badly needed after all…
How exactly you’d implement that is not really clear to me (after all not all news videos are routed through the white house) but I can understand Trumps handlers for having dearly wanted such a switch… 
edit:
Btw, the way it’s written here it looks like this senator believes Biden has an actual implanted chip which prevents him from speaking or something. And if you don’t look any further you could understand his questions like that. But he’s actually talking about a switch in the studios where he’s talking. which is a lot less far fetched and a lot less kooky. Still very implausible, because the WH would need to rewire every studio Biden speaks at without anybody noticing, but not actually technically impossible. Such censor switches are standard in all live event mixing desks I think, though normally it’s the director of the live show controlling it. You could theoretically make that remote controlled. Or you could plant a handler at every location where Biden is speaking. Very implausible that ‘they’ could do that without anybody noticing but still…
I think it is a distraction and dangerous to make the crazies look crazier for the wrong reasons. With the story as it is presented here it’s easy to think:‘nobody will take him seriously, because it’s just too far fetched.’ While someone ‘directing (like a film director, I’m not sure if this is the right word?)’ Biden is not really less believable than Trump being controlled by Putin, depending on what you have been told.
