I'm 31 with 2 kids and an SO. I've been on my own since I was 19. My dad still helps with our bigger car stuff like tires, if it breaks down, etc. When the economy fell my SO took a 50% pay cut and still have the same mortgage and bills. My dad looks at it as doing what he can to help. He and my step-mom make much more than us and have way fewer expenses. We always pay him back and most of the time he pays before I can even object (our mechanic is a close family friend). He would rather us owe him a few hundred and still have the money to spend on our kids. I don't always like it. I'm very independent and it's hard for me to ask for help. I'm just extremely thankful that in those situations my dad can help.
I think it depends on the situation. Is the kid spending all their money partying and stuff? Or are they doing the best they can with what they have? Are they in school making good grades?
My family is very much "help in whatever way you can". When my mom was out of work and waiting to be approved for disability, and I was in a much better financial situation, I paid her mortgage and bills for two years. I'll never get that back from her but it was worth it to not see her lose everything.
High Priestess JessMess, follower of the Goddess of the Coiling Way and Confiscator of Concoctions in the Order of the Curly Crusaders