My mum met my dad at 18.
He is a violent alcoholic who has battered her on numerous occasions, also been abusive to me and my siblings. 50 years later she regrets it so very much and feels she has wasted her life. My siblings and I all have "baggage" as a result.
This is how it started - he didn't like her even going for a coffee with her friends or even her sisters.
Her sisters tried to warn her she wouldn't listen. He first hospitalised her just after I was born. This was less than 5 years after they met.
Abusers don't start with hitting. They start by isolating, controlling, emotional blackmail, love bombing...
PLEASE don't be trapped by this messed up kid.
It's highly likely you will find out that his dad/step dad abuses his mum, he's copying what he sees at home.
He needs help with that - but NOT from you, from professionals with the tools and distance to deal with it.
You need to protect yourself. If you were my dd I'd be watching you very carefully for his escalating to violence.
Your mum will be too scared to be as blunt with you as we are as she will fear pushing you further towards him and away from her protection.
If she has ANY idea about any of this she will be worried sick! And for good reason too.
You deserve SO MUCH Better. At 16 your life should be about fun, school, friends, exploring, becoming an adult freely... Not being controlled and manipulated.