I quickly went through his videos. He basically takes parts from the same map or other maps and superimposes them on screenshots to envision a redone layout. As in its all just photoshop.
I did this previously in a thread for the Renewal rework dev blog as I disagreed with some elements of the rework before it came out.
I had a look at the youtuber's ideas for Battle of the Bulge and El Alamein and uh..... let me say he shouldn't be hired.
If you want to see someone who is doing good things with portal have a look at Battlefield Dad's videos.
He has a videos showing how to implement custom capture locations / map boundaries / map icons and other things - he is one of very few people who is going into depth with tutorials for the logic editor.
