My Father Is Suffering From Advanced Parkinson's And Cannot No

My father is suffering from advanced Parkinson's and cannot no longer swallow. The doctors told us a PEG tube was not a great option for him because it will require another surgery (he is 88 years old and also has a heart condition) and because he could still potentially aspirate even with the tube. Is that actually possible? How can you aspirate if the tube is bypassing the mouth?