My daughter was 19 months old when they took her adenoids out. She had been on medicine for supposed sinus infections. I had her referred to an ent and found out that she had little space to breathe out of during the day and none at night. She had surgery 3 days later and did beautiful. She later had to have her tonsils removed when she was 11. It is better to have them removed when they are young they recoup faster from what I have seen. Have the doctor check your sons adenoids as well. Until my daughter had her adenoids taken out she was being treated for asthma and sinus infections. After surgery she has not had another asthma attack, nor is she on asthma medicine. She is now 15. I really hope this helps.