I don't know of anything that will be similar to malabrigo AND will be washable, off the top of my head. However, I think that Dreams in Color yarns
has some really yummy stuff. I am not sure you would find a color that he will like but there are a couple that are fairly muted. They really are super soft and squooshy. It won't look the same, by any stretch of the imagination, but still perty!
oooh another thought is to use SWS like she uses in the palindrome pattern. The Natural Slate
might work semi-perfect for him!
eta... oh wait... SWS won't work.
it isn't washable. Sorry about that. It was the one I thought of that was most like the texture of Malabrigo. *sigh* sorry.