The neuter is nothing to worry about - they just cut the skin, without cutting through any muscles or anything. He'll be minimally sore and will feel like playing and being his normal self as soon as he is awake from the anesthesia.
Declawing is a totally different story. It is a horrific procedure - as others here have said, it is amputating all of his toes at the first knuckle! It's every bit as painful as you might imagine, and studies have shown that laser declaws do not decrease the pain during recovery.
Here is some information for you to show your parents:http://www.declawing.com/http://www.softpaws.com/http://www.maxshouse.com/facts_about_declawing.htm
Lots of people think declawing is a manicure or sort of a "permanent nail trim". Sadly, nothing could be farther from the truth. Your cat needs his toes just as badly as you or I need ours!