How can we stop my grandmother from being robbed?

Cancer doesn't make you lose your mind. Not even the pain medication takes that away, it may make her sleepy but she is still competent to give her beloved items to her friends.

You are a long way away and she has had a life that you have not seen, so let her do whatever she wants with her belongings, quite frankly it is not your business until she is dead and gone, until then she can do what she wants.

I don't know that I would trust the caregiver, maybe she is the one taking expensive items and covering it up by accusing others, you don't know what is really happening, maybe your aunt will be able to clarify what is going on.

I am sorry that you are losing your grandma, but let her go out how she chooses.

I understand your concern considering your grandmother's current health state, but there may be another side to the story. My mother drove an elderly neighbor to club meetings and later when she was a widow to doctors' appointments for several years. After arriving home one afternoon, the lady picked up a candelabra from her side board and told my mother she wanted her to take it home with her as a token of her appreciation for Mom's help over the years. When Mom protested that was not necessary, the lady told her none of her children or grandchildren would be interested in having the candelabra and she would rather give it away now to someone who appreciated it than leave it for her kids to deal with. About a year later she gave me a ceramic figurine I had once admired. This lady kept an immaculate house and I came to believe not only was she "down sizing" stuff she was also down sizing the amount of dusting needed to keep her home to her standards.

Your grandmother may be giving her friends purses and costume jewelry and other stuff she doesn't think your generation would appreciate and her friends are happy to receive and enjoy wearing/using. Once she started making gifts, other friends may have heard about it and starting asking for something they want/admire. Seniors, particularly those who were raised during the depression or WWII, do not like to see anything unused or wasted and would rather give it away to someone who will use and appreciate it.

If your grandmother and aunt are unconcerned, I don't think you should be either. Until she dies, your grandmother's property is hers to dispose of as she wishes and the will handles the rest.

You heard this from the caregiver, yes?

So, you called your aunt about it and she said...?

The only way I can see this happening - with no one intervening as a matter of course - is that the rapacious people are friends of your grandmother who are being welcomed into the house as visitors and are then - bizarrely, but there's nowt so queer as folk - nominating their own keepsakes. Which I personally would find repellant, if it's happening like that, and if I were your aunt I would give them a "have you lost your mind" look; but then again isn't it more likely that your grandmother is actually giving things away while she can?

Even very expensive purses, once pre-owned, are not things that nobody would give to a friend.

If your aunt is there and there is a caregiver, who is letting these people in?? Is there not a competent adult who can lock the door? And call the police when these people show up? Your aunt is there. She needs to take control of the situation.