Are detanglers compatible with handlebar stem extensions?
 

I am a total noob when it comes to bikes outside of just basic riding. I'm not too familiar with all the terminology so I may not explain my situation 100% correctly. Recently my buddy handed me down a Mongoose 20" bike that his son has outgrown for my younger son to use. This bike is equipped with a detangler and the front brake cable comes up through the center of the handlebar stem. The bike seems almost perfect for my son but I think the handle bars should be a few inches higher than they are. I've seen handlebar stem extensions on the market but none of them look compatible with how the front brake cable comes up through the stem. I wanted to attach photos of what it all looks like currently but I guess I'm too new here. I appreciate any help I can get.

It's really just a hollow bolt set up. Probably easier to find bars. New school bars come in heights up to 12 ". Many of the old bars were short as bmx were originally kids bikes. Now most pro's are 18+

the one surrounding the headset is for the rear, so you can do handlebar/wheel spinning stunts.. In the bike shop we were usually removing them..
Id look for higher rise handle bars , in your situation..

it sounds like you want a taller handlebar. for a casual urban bike, a stem heigh extender is fine. of a BMX bike that is to be ridden like a BMX bike, a stem height extender sounds like a trip to the emergency room.