Thank you for your clarification.
There are two ways to approach this:
1) You can wait and see what CPS decides to do. If CPS believes mom is negligent they will work with the father in getting custody to him and create a custody order. In essence the children will be part of a dependency case, monitored by CPS (whether informally or through the courts). Your spouse should ask what he needs to do to prepare if the children are being neglected to get custody of them (such as travel to AZ), possible court hearing, any documents they would need for him to bring.
2) You can initiate a custody order by filing the petition for custody in the homestate of the children. If there is an urgent need to protect at the time
you are filing you can in addition to the petition file an emergency custody motion. In order to get an emergency custody, an existing custody case must be already filed, so your spouse would need to ask the court clerk in the county where the children live how quick the petition can be set.
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