To contact cousin to tell him I support him about his toxic mother.

[JosephineBucket]

While I never had the closest relationship with my cousin, we grew up together and I miss our connection to our childhood. He went LC with his mum/my aunt when got together with his long-term girlfriend and had a child together - she feels like GF has ruined their mother/son relationship while he feels like she's a boundary stomper who has no thought for anyone other than herself.

He has now cut all contact with the family - I've never taken sides but he is assuming we take aunts side. Since joining Mumsnet and reading about toxic relatives I recognise a lot of her behaviour towards him as narcissistic and considering I've only heard her side of the story she's either totally unaware of her behaviour or she's worse than she is making out.

I'd love to have a relationship with him separate to his mum but aware I might come across as a flying monkey. Is the relationship unsalvageable and if not how do I to about it?

YWNBU. He might appreciate contact, he might not. But you'll only find out if you get in touch.

I think that sounds a great thing to do. I'm sure you can word it to make it clear you're not a flying monkey.

Yes, definitely reach out. Be ready for rejection though, depending how messed up he's been he might be paranoid about contact.

I'd say Christmas gives you a good reason for getting in touch, and you can keep it really low-key and neutral. A friendly message in a card, maybe a gift token for the LO, don't overwhelm but make it clear that you remember your childhood relationship fondly, and would like to see more of him. A positive message about the niece/nephew you'd like to know better would underline the message that you don't share his mother's opinion of his choice of life partner!
He may not be ready for this, so don't press the matter too strongly, but if you don't succeed, at least you can console yourself that at least you tried.

Yanbu. Being believed can be wonderful!

Do it!