Your H sounds depressed to me. Does he have any goals, dreams, motivations? If he was obese before and only overweight now, at least he’s got some drive to move back in the right direction, but my question is why did he get so obese in the first place? Overeating is often a cover for other problems....
That could easily just be because he had his testosterone corrected...for a while. "obesity" isn't always from over-eating. that is actually a symptom of low testosterone...as is depression.
nevermind all the psycho-analyzing; he's got medical issues that need to be addressed. None of this other stuff is even pertinent. until someone has an appropriate amount of sex hormones going through their veins, they're just not going to be interested, period. You could be "Marilyn Monroe" and it wouldn't make any difference. Nothing you did or didn't do or his parents did or didn't do has anything to do with it. (at least...not yet, anyway).
remember, this is why we neuter dogs and cats and horses, etc. so they won't have any interest in this sort of thing.