Back in high school, I had a swollen lymph gland that required draining too. It grew very quickly and started pressing on my throat too. After the draining, I was fine, it never came back. Check with his doctor to see if it is okay to hold off on the surgery. He may have to go back to have it drained before then, but that should be okay. You don't want it closing his throat, so be sure to watch it closely.