Is the tonsilectomy a risky thing to do?

Not usually. Scariest surgical risk is postoperative bleeding. For anesthesia, usually goes fine, though airway surgery always carries risk of obstruction. Anesthesiologists tend to be more nervous with obese people getting tonsillectomy for sleep apnea than with treating chronic tonsillitis. Vomiting very common, though meds have really improved this.
No. There is always risks involved but this is a very common, simple procedure.