I know others have said that he's old enough at 16 to choose how he spends his time, but I'm of the opinion that this shouldn't be the case if it's going to be detrimental to his long term wellbeing - and I think screens are more of a problem in our children's lives than we're willing to admit. At the age of 16, young people only know what they know (if that makes sense), and they still need a firm, guiding, parental hand to steer them away from bad habits.
I wouldn't ban it outright, but what we do is to make sure we all eat together each evening to catch up on the day, and there's no devices allowed at the time, so that's a start.
I would also try and plan things to do that don't involve screens, such as walks and days out, for the whole family. Also maybe ask him to do little tasks for you like walk to the shops, or something, and suggest maybe watching a film together (which I know is still a screen but I do think it's different).
I just worry that at the moment we're creating a zombie generation who don't know how to socialise effectively, and as parents we should be encouraging activities that are more productive or beneficial.
Our 16yo is allowed an hour on his PlayStation each evening, though we're pretty easy going at the weekends and he's free to go on it so long as he's up to date with homework and we're not going out anywhere. When he's not on, he will either read a book, or come and chill with us and watch some tele - which is at least a little more social.