We don't know anything about his son really. There was only one picture of him available until recently and he barely made it into NK media.
Over the past year or so they've started to worry about succession, so he was introduced into the north korean propaganda campaigns and was given several titles(military ones especially) that will make the people give a shit about him.
If they fail to extend the cult or the personality surrounding the "Kim" family to Kim Jong Un, there will be a military coup by others in the Kim family.
