Waiting and worrying is very hard. I used to have a friend I worried about too. Once he stood me up and I started calling hospitals to see if he was there. It turned out he was fine in a bar somewhere and chickened out on calling me to cancel. Could never understand it but I learned not to go crazy again. There is nothing you can do but call & leave messages as you have done. When he's ready, he'll get in touch. If, g-d forbid the worse happens you know you didn't abandon him and he will have known you always cared. That is special.