Elizabeth,
Have you checked with the military to see if they help your daughter? I would try to contact the base where SIL is stationed stateside and see what info. you can get. You should also contact a military attorney to get your daughter help. There should be some record made of the abuse for future problems. Your SIL is responsible for finacially supporting his family and the military will make sure he doesn’t stop sending her money. I believe they will even deduct money from his pay and send it directly to your daughter. DO NOT do this on your own! Get the military involved for your daughter and grandkidsprotection.
Ginny