My Son Has Just Completed Aggressive Radiation And Chemo Treatments

My son has just completed aggressive radiation and chemo treatments for throat cancer. He is on a feeding tube. A lung ct was done and we were told he is aspirating all the liquids he drinks into his lungs. He now needs to have therapy so he will be able to eventually drink and eat again. This is due to the damage of the treatments. I have read about numerous cases and no one has mentioned this problem. Is this normal and is it in fact curable?