Are radically changed eating habits a sign of some kind of nervous or health disorder?

I am not talking about diet changes like becoming a vegetarian, etc. By “eating habits” I mean the way a person eats his food.

A few months ago I had dinner with a 60+ friend of mine and noticed that his eating habits had suddenly changed dramatically. When the food was served, he immediately started to cut up his food into little pieces. Fast! Really fast, and with a surprising, almost frightening intensity. Meat, mashed potatoes, vegetables – even cottage cheese. Also, he ate it very quickly. His plate was empty in a few minutes. I didn’t say anything of course figuring it was a fluke. But recently another person mentioned eating with him and noticing the same bizarre behavior. His wife even said something about it to a mutual friend. Again, nobody has said anything to him about it – after all you only notice it when he’s wielding a sharp knife and fork.
He is in otherwise good health. He is not dieting, nor having stomach or digestion problems.
This week someone else mentioned that he has begun to suck food off his utensils rather than place it into his mouth.

What could be the cause of this? Is it possible he had a mini-stroke? Should we say something to him? Has anyone here ever seen this kind of behavior? Is there something we should do?