A few years back she had called asking for his ss# and his dob and a few weeks after a woman called asking to speak to him .She said how was everything going and if it was working out he said i dont know what you mean she said your daughter as your new care giver ! He lol said hun did you apply for funds to care for me i said not yet why dad .So he asked name it was my older sisters and the lady said it was fraud but never revieved a call from her again.
Did you ask your sister about it a few years ago, when it happened? From what you've written it does sound like attempted fraud by tour sister, but the agency caught on to that and no doubt took cake of it.
If your father is eligible for some assistance, perhaps you should apply for it, legitmately.
This person who called you, might well have been fishing for information from a vulnerable senior, and believe me, they are out there!
A simple call to your sister should be able to clear this up, and in the meantime, see if you can find out who it was that called. Do you have caller ID? Another thing, is your Dad "with it enough", to answer calls, and know enough not to give out personal information? I know my FIL who lives with us is very uncomfortable taking calls, and while he might have some early Dementia, I would say that he is still quite "with it", but the types of vultures have a way with putting people at ease, making the elder think that they are just "there to help".
If you do investigate, you may find that your Dad has been hacked in some way, and should check into it before it's too late!
You do not need to be accusatory towards your sister, as there may be a very good reason for the call, and she may be looking into ways to hel, but didn't inform you first. But make the call, for your own peace of mind.