Child becoming agitated. Addicted to technology?

We temporarily have gaurdanship of my boyfriend's little brother. His mother who rather be a friend than a mother. No bed time, she never cooks, (buys him mcdonalds everynight) no restriction on technolgy, never takes him outside to swim or to the park, nothing. They just sit in their house and watch TV all day.

She's never encouraged him to play outside or interact with other kids so he plays on his xbox, tablet and handheld video games all day by himself.

Not in my house. We are productive here.

He will have a complete meltdown when we need him to put the game down. He will scream, cry, kick, yell and honestly I think my neighbors will call the cops on me one day thinking we're abusing him. I'm not trying to change him, but rather ween him off his addiction a little bit.

How do you deal with a child who was raised with little to no discipline? All I want is for him to interact with other children, go outside, just be a kid.