You can just adjust any cleat so your feet doesn't float "in". But if he wants to ride with a foot pointing outwards that will force the foot to pedal straight, risking injury
I didn't suggest speedplays. Just answering your question. You can limit inward twist but yeah you want the natural angle. Speedplays come with all sorts of length spindles though so potential for no extenders there too.
You can just adjust any cleat so your feet doesn't float "in". But if he wants to ride with a foot pointing outwards that will force the foot to pedal straight, risking injury