OK, so there are a number of issues here. And last time I posted my views on this topic I got a few quite negative comments, but here goes...
First, I wouldn't be thinking of a 16 yo as a child.
Second, if you insist he goes with you, how would you enforce it? He isn't a toddler who can be picked up and carried. Tbh, I think you would be on pretty shaky ground - he can legally leave home at 16 after all (although technically he needs your permission until he's 17).
Third, if you haven't yet left him alone I think you're leaving things a bit late. When do you think he will be old enough? 18? I absolutely agree it should be one night first, but that should have already happened, IMHO. From about 14. Then the occasional weekend from 15, so that he's ready to be left indefinitely from 16 (as he can legally do).
Our DS2 lived by himself from 16 to 18, while he did his A levels. I got some very negative comments last time I mentioned this, but it was fine - it was his idea, he lived in our house, we paid for everything, he passed his exams, and he didn't trash the house.
The teenage years are for learning how to be an adult. They can't learn if they don't get a chance to practise.