hey I'm exactly the same my lower left tooth OUCH! tell him to try clove oil very disgusting but effective for a while, just strong pain killers and hot water bottle on side of face should ease it that worked for me a little. Sounds like he has got cyst inside of his rotten tooth that what i had i went hospital and they gave me loads of antibiotics to get rid of infection and STRONG painkillers they just knocked me out lol hope he sorts it Jenny