They will be able to take the needed actions to get things sorted out and work with the court system in the STATES. Although his pay can be garnished if the court orders it, the JAG officer should be able to make sure that the amount paid if not unreasonable and puts a needed burden on the rest of his family.
Visitation is his right, he needs to petition the courts for it. But, with him being in the military and stationed overseas, it might be difficult to carry out.
If you have internet access, visit the various links online about child support for your particular state, etc….
Some base the amount of support on the percentage of income from both parents as well as the number of kids needing support.
As for “CAN they do that”…… who knows what they can or cannot do, other than a lawyer. Seek out your legal counsel and protect your rights by visiting your JAG officer ASAP!