Voice control

I have a Chromecast With GoogleTV. I set it up to control via a Google Home Mini. My father is handicapped and can’t use his hands well enough to use remote.

Here’s my question. Our TV service is YouTube TV. When we say “Hey Google turn to ESPN” it changes to ESPN but it is being cast. If I grab remote and press home and open app it’ll be on whatever last channel watched in app is. When I am watching with him and we want to scroll through the guide to see what’s on and I select a channel it works but when he goes to change the channel by voice it leaves app and goes to casting.

Any ideas on how to always use app?