jen, its abscessed.
any swelling indicates infection. 2 to 3 months now? tooth probably will come out.
naproxin is the same as alleve, and ambasol is similiar to iddee's suggestion on the oragel.
have him try as i said to reduce the pain until he can get in:
2 regular tylenol (325 miilligrams each tablet) , or extra strength tylenol (cut in half to start out, one tablet is 500 milligrams) and take with two naproxin/alleve (one tablet of alleve = 220 milligrams). once in the morning, and before he goes to bed. mid day just have him take a dose of the tylenol, regular 2 tablets, or extra strength, cut in half. this should reduce the pain, but will not take care of the infection.
if using tylenol extra strength at half dose isn't cutting it, have him take the full tablet. and lots of water.
not sure why his dentist is not giving advice to manage the pain until he can get in?
my tolerance for any pain is high, but not when it comes to my teeth.........
i am not a doc, but i learned a few things in back country medicine without the aid of narcotic drugs that kill pain. hope this helps.