He needs anti inflammatories rather than just pain relief, so he should take ibuprofen. If it is a trapped or nipped nerve, the swelling will be making it keep catching, so getting the inflammation down is a priority.
Hot bath, maybe with a good muscle relaxing bathsoak (like radox muscle therapy) Then i find a heated bean cushion applied to the area helps.
He may well benefit from visiting a physio or chiropractor to give him some excersises to strengthen his muscles in order to keep everything in place. He must make sure he carries on moving around, as imobility will make it worse.