you shouldn't be watching TV when you are driving.
And you shouldn't make passengers so happy, they will not listen to you or
help you in driving if you keep them busy with TV.
Does your audio system not have an audio in, or aux input? That's the way to do it.
If not, You're stuck with one or the other. Given the choice, I'd much rather hold the phone in hand and stare at small screen with nice sound than have a bigger image but no real audio.