Quote: "The graphic style was created by my son."
Not sure what graphics program you are using, but I like Paint.NET
, which is FREE and Open Source with lots of cool plugins.
Just watch out for the ads on their page that are disguised as download links, but once you hit the right download you will enjoy.
The user interface is much like Microsoft Paint, which most people are familiar with, only it is better with many more features.
There is a nice ICON plugin available, as well as DDS compatibility, so it can be useful for 2d and 3d work.
When compared to other software in its genre, it is either cheaper, or easier to use than its competition.
At his age, he has great potential for graphic work.
Coding things my way since 1981 -- Currently using AppGameKit V2 Tier 1