Everyone take a deep breath
All of your answers can be found in AR 608-99, period. Having been a commander and unfortunately having dealt with these situations, this reg is your friend. Lots of mis-information out there, but generally, the Army doesn't want to get involved in civil matters, ie. divorces. The rule is the Solider must provide support or their share of support equivalent to the amount of her BAH. If this Soldier has children from a previous relationship, and he pays support, she wouldn't get full BAH, etc. However, there are exceptions. Including no support if she is living in gov't quarters, or a valid court order detailing what support must be paid, or a valid agreement between both parties, etc. Regardless, this Soldier's commander will only be able to do so much. I cannot dispense additional advice, but would point anyone to the reg.