Is he old enough to pick which is his favorite?

yes he is 4 he like red

Hello there! If he loves red, I would find a pattern that incorporates red, blue and gold/yellow. The bedding sets below are from Ikea. His interests will change so quickly - buying inexpensive bedding will make it easier to adapt to his new interests every few years or so.

Have seen a spread that made the bed look like a red car - would go great and be loved

Sometimes the bedding can be plain and with those colours a Lego theme would be great http://houzz.com/photos/302734

http://houzz.com/photos/764177