Legal Question in Family Law in Missouri

If you get a written and notarized statement form both parents giving you temporary custody of the kids, then you can enroll them in school and most other things a parent does. This should be temporary as many beat the one year prognosis. If, God forbid, your sister should pass on, then the father can grant you custody to house and care for the kids then.

Good luck

There is a statute which allows a Court to name a third person the custodian of minor children in cases where the parents are unable or unwilling to exercise custody. In your case, you could take the step-by step approach suggested above, by having one of the parents sign a power of attorney once a year. Or, you could file a Petition with the Court and obtain a judgment naming you the custodian of the children, subject to rights of the father to have parenting time with the children and including child support as well.