There are many factors involved there.... How long was the marriage? Is any support being paid?
Military Disability can be garnished but NOT in the normal way and is subject to an entirely different set of rules. Disability of this sort cannot be garnished through the courts it has to go through the VA and they have a completely different criteria they use to determine of the request should be granted. You would have to apply through the VA, and their criteria or very different. They are concerned with the servicemember NOT the children and they will make their decisions based on a whole different set of facts.
In my case my ex was making token payments, so even though he was already thousands of dollars in arrears and making nowhere near the court ordered payment they declined to grant any payment as they decided the NCP needed it more.
