Unless something is changing from current law, and I've heard nothing that says it is, a 529 isn't opened for any particular school/age.
Each parent and each grandparent can create and contribute to an account for each child. Any of those funds can be used for any qualifying educational expense, the definition of which may be expanded to include K-12.
So parents and grandparents can each open one, and K-12 private or college expenses can be paid from either or both.
Or one parent can open one for a child and everyone can make contributions
The account owner is the person who opens the 529. As the account owner, this person manages the college saving plan: selecting or changing the beneficiary, selecting the investment options, making withdrawals, terminating the account, and receiving withdrawals if no other person is designated. The account owner also makes contributions to the account, but others can help, too. Anyone can contribute to an already established 529, but only the account owner controls and sees the assets within it.
The account owner, typically a parent, opens the account for the designated beneficiary, typically their child. However, grandparents, other relatives, and friends are all potential 529 plan account owners. The account owner does not have to be related to the beneficiary. The owner designates the beneficiary, sets investment allocations, and, ultimately, controls withdrawals from the account.
Depends how much the grandparents trust the parents, I suppose.
