What hairstyles can I do in my son ?

Destiny

He has very beautiful curly hair but most of the time it looks like this haha. I can’t really flatten it with gel or anything cause he’ll look sorta bald since his hair is so thin. What kind of styles can I do without cutting his hair ? I also tried a curling mousse but it wasn’t too good maybe it was the brand but it was basically like gel and didn’t look good.