Question about 16 year olds

So I just wanna ask are 16 year olds children? My answer is yes they are cause they’re underage but no they aren’t cause they are at an age where they should be more independent is that not right? I have a situation going on with my brother in law who’s 16 and is super dependent on me and his brother, we’re married for 7+ years now. I understand that you know it’s a young age and it’s to be expected I know I get that but in detail he needs to be told how to do something over and over 5+ times and we’ve showed him every time. For example cleaning his bathroom to bleach the sink and tub. Another is we have a super simple air fryer and we’ve taught him 2-3 times how to use it and he says it’s too complicated to use and he was only trying to cook breakfast sausages. On his phone he makes these cool videos that’s 15-30 seconds long and they are really good and I know takes time to make them. So I’m wondering if it’s just cause he’s 16 but why can’t he apply himself like that to his own living to try to be somewhat independent??

I just feel like, I’m 25 right now, when I was 16 I wanted to be independent as hell and not want to be so dependent on anyone. What happened to that? Why do we look at these kids now like they need to be hand held all the time and let them be so dependent on us? I’m not trying to make excuses but when do I say enough is enough? They have the privilege to learn on their phones how or what to do with something anything. We did too and I can only imagine generations who didn’t have the luxury and privilege. Again I get it it’s just how they are cause he’s the age but also he turns 17 in a couple months. I just idk I need to hear what others have to say.