I agree with the other comments. He must try to see other channels and copy some of the tricks and one day find his own style. He must start to talk to the camera.

Some channels to copy^H^H^H^H look:

* ElectroBoom: https://www.youtube.com/c/Electroboom

* Cody's Lab: https://www.youtube.com/user/theCodyReeder

* Applied Science: https://www.youtube.com/c/AppliedScience

* Simone Giertz: https://www.youtube.com/c/simonegiertz

* EEVlog: https://www.youtube.com/c/EevblogDave

Some are more funny, some have more charisma, some make more difficult project, some make weird projects, some like to rant, ... They are very different, but your brother can get a few ideas.