P.B.
Have you tried an inexpensive tape player that he can use himself? You can record a song, a story, or a message of love for him that he can play for himself (most tapeplayers do have auto-stop, so you can just let him turn it on himself.) Tell him to try the tape before calling you, then see how that works. You sound like a good mom -I wouldn't have the energy to play most of the evening with my children if I worked full time..More power to you for all you do!