hun.... it is hard isn't it.
Is there any way when your on chat with them you can say have you tried.......
As an example take co-sleeping...

Have you tried co-sleeping at all, yes it can take some getting used to but it can be less tiring for the 2 of you (mum & bub) and it's a great bonding experience, i did .. xyz and thats what worked for me but each to their own.

Make it a casual conversation, they may not be getting that kind of support from other friends and family, especially the person who's 1st, you always get people asking if bubs is sleeping through yet etc, maybe she feels she NEEDS to say yes and is desperate to try anything.

I don't see anything wrong with you being upset about it but rather than loose friends over it maybe next time mention BB, gentle parenting, settling techniques.. any little hint that makes YOU feel better, that you have atleast offered a 'friendly' solution.

I'm probably not making any sense...