My son is an adult now, but when he was a minor:
I had a will stating my wishes. Oregon has an automatic custody of child sequence that I highly disagree with, especially since my ex never looked back when he left (my son has not seen or heard from him the ex since he was around 9 years old). I knew if the ex got custody, he'd just dump my son with his parents (which would be an extremely bad situation). So, I put in my wishes that my sister would get custody, so she'd have something to take to court to prove that is what I wanted.
All my money and assets would go to my sister to control for my son. That way there was no way my son would "come with money" that my ex could blow on alcohol, or the in-laws on whatever they wanted. It was to cover expenses that come with raising a child, his college, future down payment on a house, etc. I fully trusted my sister to handle the money appropriately.
My sister was also made the beneficiary on my life insurance, again with directions in the will on how it would be handled.
Now that my son is an adult, everything is back in his name. However, before then, I just had the rule that I could not die before he turned 18, because I did not want any chance of my ex or his family getting custody.