My best friend has 9 adult children, all breast fed as babies, all brought up, I think, very successfully. But when she offered some advice to her second daughter about her daughters first baby, she was told in no uncertain terms, ‘You know nothing’. Likewise, I’m a very experienced HV but have been lectured by (usually) darling SiL about the benefits of breast milk, baby sleep, etc, etc.
I think that we have to learn to ‘zip it’ as regards advice and as others on this thread have suggested, care for our grandchildren lovingly, don’t offer what may be seen as unwanted advice and then generally get out and enjoy ourselves with friends on our ‘days off’.
In fact, at the moment I’m on a sunny island on my ‘days off’ (love the Hotel WiFi) and lots of the possibly unintended criticisms from SiL, etc, have receded somewhat while I think about where DH and I can go for another swim and then a drink before dinner! ??