Is my friend right to sue his workplace over this?

All he did was help put some trays up (in the restaurant he works at) and his shoulder started hurting. He tore a ligament or something and says it's a permanent damage. Has to go to physical therapy. But he's making such a big deal about it, suing the owner and his insurance company. Got 2 lawfirms on it. It's not like there was something faulty or anything, he was just basically working and puting trays on a shelf. I feel like he's going overboard trying to sue