If you have a court order as it relates to custody then it should address this specifically. If you do not, then there are several questions that you probably need to answer and it would probably be wise to get have a court order as it relates to custody, I would suggest hiring an attorney to do this. Also, does he currently pay child support? do you think the reason he doesn't want to tell you has anything to do with paying child support? If you do not have a court order as it relates to child support, either hire an attorney to file a claim for child support or contact child support enforcement and get it filed asap, while he may have a very small obligation while he is in school, once he has a regular job he will be required to support his child consistent with his income, and your child is entitled to the support from both of her parents.
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If there is a court order, it should have specifics regarding moving and/or updating the other parent of address changes within a certain time period.
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