I am new here so a hello from me

I have tried using search to find a solution to my problem bu could not find anything. I am sorry if this has been posted before but i could not find it.

My problem is with my 1.3 1984 escort and my boyfriend!

The cam belt needed changing and he said he knew how to do it. He lined all the cams up with the notches but he didn't lock anything off. While getting the old belt off he let the cams (i think they are called) slip out of alignment (by accident). Anyway he lined them up again, put the new belt on and put everything back together. Now the car is just turning over with a (very quiet) knocking noise. He says he may have bent a valve and is going to take the engine apart to have a look.

Is it a good idea to let him do this? What could he have damaged? The car was fine before he touched it and he even said the old cam belt looked new!

Any help please?