B'day present for 4 yo boy with muscular dystrophy - any suggestions?

[Malaleche]

DDs classmate has some form of muscular dystrophy, he can sit up using a back support and eat unaided but cant walk or crawl. He zips about in an electric wheelchair sometimes when the terrain is suitable, which it mostly isnt in this town...
Will probably just get him what i would any other 4 yo - a simple board game or maybe one of those observation boxes for lookng at insects or similar - but is there something i could get him that he or his parents would really appreciate?

Ds1 loves his Aquadraw, but this may be a bit young for him.

A REALLY cool t shirt, with his favorite character on it?

Playdoh fun factory?

playdoh is a good suggestion(dd has cp and loves it)
if he can use a pen. sounds boring but elc felt tips are BRILLIANT as they wash out.
and games wise. puppy races is really good.

thanks for suggestions, will have a look round the shops tomorrow...

How about a small remote control car or similar, woolworths do cheap ones, my ds2 is 4 & loves them.