We're talking about the US here. Most 18 year olds do not have the ability to acquire their own healthcare AND afford their own housing.
Even aside from that, when a young person starts a family for the first time, they often lean on their parents for advice because this is life experience they don't have and there are plenty of issues that someone without that experience would not anticipate.
This person did not revoke financial support from her kids. She revoked emotional support from them.
With regards to emotional support, it sounds like her youngest child was close to 30, so I don't think that's a big issue. Of course it's nice to have contact with your mother even if you're 30, but it's a bit rich to suggest she "abandoned" her grown children. Presumably she discussed it with them first.
And most likely the kids married people that had at least one parent to get parenting advice from.
My only point is that it’s absurd to talk about “abandoning your children” when these children are close to and over 30!