Is removal of tonsils a "must" for sleep apnea?

No: It is not a must, but if you have large tonsils blocking your airway it might be a great idea. Many people who have sleep apnea, don't even have tonsils, but if you do, talk to your ENT or primary care physician to discuss your options.

Only for children: Tonsillectomy is the first line treatment for sleep apnea in children. For adults, tonsillectomy will not cure sleep apnea, it is not normally recommended unless tonsils are unusually enlarged.

Depends: It depends on how old the patient is and how big the tonsils are. In children, removing the tonsils and/or adenoid is very helpful. For adults, it can be more complex. Often, CPAP becomes part of the picture and nasal surgeries complement its use. Weight management is critical regardless of age if the patient is over a healthy weight. See an ENT who can talk about all of the options.