Rafi still can’t play regular solitaire by himself, but I remembered a different version of solitaire that is much simpler. Idiot’s Delight: so easy a four-year-old can do it!
I taught him the trick of re-dealing the remaining cards after you lose so that you always get to win, eventually.
Sometimes he plays by the real rules and sometimes he makes up his own variations. Sometimes he wants company…but he never, ever needs help.