Adding an iOS Device

I understand that downloading the HA app to your phone and logging in will automatically integrate the phone to HA. However, is there a way to integrate a phone or tablet without the need to put the app on that device? I want to add in my son’s phone to integration but don’t want to put the app on his phone. I have added via iCloud integration so I can get battery level and presence but I’d also like to see which app is currently being used.