timing belt broke on freeway, engine damge possible?

What is your question?

My brother just broke his timing belt on the freeway. He said his car seemed to just lose power and he pulled over. I asked if he heard anything grinding, ticking banging ect. he said no. I am wondering if he did damage to his valves, pistons or anything else. Is there any way to determine or at least get a clue of the damage without taking the heads off and inspecting for damage? He drives a 2001 Mitsubishi galant. I am a A&P mechanic so I plan on doing the work for him