i think in this age of mobile phones, email, whatsapp etc, one of the biggest problems is that many parents, especially mothers never really seperate themselves from their children when they grow up.
I have talked on other threads about the physical umbilical cord that is detached at birth and the emotional umbilical cord that is severed in adulthood, usually when a AC enters marriage or a long term relationship.
When I went to university, my parents would at best get a letter every week or so, giving them an (edited) version of my life. I was able to grow up, make mistakes, do all kinds of things that would shock my parents and earn their deep disaproval - if they had known about them, all without my mother on the phone, whatsapping me, sending emails etc - and she had to learn to get on with her life with me not there.
In the past if conflict arose between parent and child, the child could just move away, only ring or write once every so often. I had a friend where she and her husband chose a house that was not easy for her mother to get to without a car. She still saw her mother regularly, she was an only child and her father died when she was a child, but her mother wasn't in contact every day or calling in all the time. She could cope with her in small doses.
It seems to me too many mothers are not cutting the emotional umbilical cord. They need to stand back, say nothing, get a busy life, so that their children while still deeply loved, are not the centre of their lives, except in emergencies.
There were plenty of estrangeents or near estrangements in the past. They were just well hidden. two of my father's brothers were virtually estranged, but no one outside the family would have known. One was in the army, married young and used his army postings abroad and to remote parts of Britain as an excuse for rarely seeing or contacting his parents.
For most parents the advice is cut the emotional umbilical cord, leave your children alone, aim at quality in your contact not quantity. Do not try to be part of their adult life, you should both have separate lives, still less offer help or advice unbidden.