My Dad didn't include Mother in his application for Aide and Assistance, How do I get Mother listed for spousal benefits upon Dad's death?

It was a lack of understanding VA rules and regulations, that Mother was not included in the original application, just a few months ago. I just want to do whatever is necessary to make sure Mother draws spousal benefits. She will be living on a $700 Social Security check without the spousal VA benefits I have read that she can apply now, while Dad is living to speed up the process in the event of his death. Is this true and how do I go about getting this and whatever else has to be done?

Sincerely

Concerned Daughter