Mary,
We really cannot advise as to how this would come into accounting, but any funds she has access to have to be disclosed. Please try to get with an Elder Law Attorney who could best guide you on this issue.
As for the documents that need to be included, please see this link from the website:
http://veteranaid.org/apply.phpThe VA will not recognize a POA so it will do little good to include it. The biggest thing for now is getting the application submitted so that it is a matter of record and her effective date will reflect that. You can fill out the application for her, but have her sign it. We also strongly suggest that you send it "registered mail" so that someone will have to sign for it and you will have proof of receipt. Applications that are mailed registered have a much higher percentage of not getting lost, or a VA claim that it was never received.