Yes, a laryngectomy, especially a total laryngectomy, is dangerous. The rate of complications depends very much on the particular patient, hospital, and surgical team. As a very rough rule of thumb, we might expect 5% rate of major adverse results (stroke, myocardial infarctions, pulmonary emboli, respiratory failure, and death). Lesser serious complications (wound healing, fistula, infection, chyle leak, etc.) are very common, at about 30%. I don't have the figures for NOT having the operation, but I would expect over 90% death within a few years.
But these are national averages from 20 years ago. Your dad is not average, and his doctor is not average. You should ask the doctor how to evaluate the risks for your Dad, for the hospital. One of the major factors the doctor has to consider is the patient's compliance with medical orders. People who say "I was healthy and active before surgery, therefore I don't have to take all these pills" ... those can be the worst. When I had my gall bladder taken out, the surgeon said his 99.8%+ success rate was mostly due to patients following his orders. But I think his having done it over 3000 times might have had something to do with it.