Befriend him and then make him your boyfriend, you being strictly a top, and verbally berate him while you dominate his beta ass.
During those moments of intimacy with repeated degradation he will begin to slowly accept those negative and berating comments as accurate adjectives that describe him as a person.
Outside of sex treat him kindly, but also be strict on certain things like weight management, curfew, style of dress, mannerisms and demeanor, etc, and slowly get him to treat you as a superior with how he addresses you.
The rules you’d put in place should come slowly, as piling tooo much on at once will make him believe you to be too controlling or unhealthy to stay with for him.
Essentially, you’re continuing with bullying him, making him rely solely on you as he deviates from his friends and family more and more as he accepts you as being the only person who can be there for him, be it emotionally, physically, and eventually even mentally as he relies on you for decision making, seeking your approval and validation before going through with even the smallest of activities, like his outfit, hanging out with a friend, etc., fully surrending himself and all power to you, essentially making it so you govern his life.