N.B.
I had to laugh, as this brought to mind a story about my daughter. We went to get ice cream when she was 2, and when we got home, she was still holding her cone, untouched and melting all over her hand. When I asked what was the matter, she couldn't speak because she had a mouth full of peas! Anyway, the walking and talking are not a concern, but if this is more than just something he doesn't want to eat, I'd have him evaluated. You don't want to overlook something that may be important.