Idle people are foolish because they are ignorant. Foolish people need some guidance to become more wise and diligent, and when they do, that doesn't mean they weren't foolish to start with.

If you do a good deed, it is inherently good. That is, even if no one remembers what you did, even if you don't remember what you did, even the person you did a good deed for doesn't remember what you did, it is still a good deed which helped that person. If no one remembers, it is still there.

I think a quick search in google can confirm that Buddha most likely said this. It does matter to give credit to whoever said this (whether it was the Buddha or not), but you should not just believe anything just because it is spoken by a great mind, but because it is true!