How many times have you posted this text????
The following is an idiom I think might have some spelling mistakes? Maybe the words "they" should all be changed to "he" as regard to the word "someone"?
A fool at 40 is a fool forever
If someone hasn't matured by the time they reach forty, they never will.
Or, maybe I'm wrong, but it's my first time to encounter such sentence pattern: the subject of conditional subordinate clause is "someone" while the subject and the object of the sentence are "they" and "them" respectively.
A little bird told me
If someone doesn't want to say where they got some information from, they can say that a little bird told them.