Select Movie from iPad

Is there a way to choose a movie from an iPad to play on a Roku with Plex installed? My mom has a small TV and the Plex interface is hard to read from her chair. Wanted to see if she could use an iPad to select the movie or TV Show to play on her TV. I thought about casting from the iPad, but I’m worried that will add a layer of confusion for her. Thanks for any help you can offer!!