I don’t understand why your/his foot is/would be coming off all the time. If you cannot spin your pedals round without your feet being strapped to them that indicates bad pedaling
technique.
I found my front foot would lift of the forward pedal, this would happen if the rear wheel got hung up a bit on steep tecnical climbs when my cadence dropped. With spd’s I could just pull my rear pedal through. Over time maybe I would have adapted to this, but for me I thought why bother, get the spd’s back on and be happy 😀