His parents don't want him dating someone because they're A YEAR older than him, at the age of 24? There's something hugely wrong there.
Answers to your questions:
1) Was it your mother's fault? No, probably not.
2) Definitely not.
3) YES!
4) Perhaps... all in all though, very asshole thing to do
5) Maybe he's an ass.... this can be reinforced by question 4
6) Avoid all contact. This is quite effective.
7) Your mom sounds spiteful.... :S

Here's my advice: move on. There's no use dwelling on it.

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"You know you're in love when you can't fall asleep because reality is finally better than your dreams.” -Dr. Seuss