Not exactly what you want but the HiMedia remote app HiControl will allow you to control Youtube from a phone. We await a new version, the current one is 1080p and Android 6 max: http://www.mediafire.com/download/8uilxt0hv70j5lo/HiControl_hmdCV200.apk
Or there are a few Youtube specific remote apps in Play Store, but I've not tested them and they get some negative reviews. https://play.google.com/store/search?q=youtube%20remote&c=apps&hl=en_GB