It's a phase and will pass. Just grit your teeth and hang on. Offer the old biddies to swap places with you. Talk is cheap.

I'm so sorry. I'm going through pretty much the same thing. I have to keep telling myself that it's not my mom it's the disease but it is really hard not to take it personally. Hugs and prayers for you

Paranoia is common, my husband used to handle finances and iof course now I do! He questions and accuses me a lot and it's very frustrating. I would most definitely have that conversation with her friends and remind them that you are there to care for her, not take advantage of her.
That bring said I'm not sure an email is as effective as a personal conversation. I Periodically call friends with updates and they really need that. Her friends possibly are feeding her existing fears not initiating them

I know it’s very hurtful but we need to not take this personally. You need to remind yourself that it’s the disease. If they weren’t accusing you of using her money, they’d find something else to accuse you of and no matter what scenario they choose, it really is just the disease. It makes people paranoid. My own mother goes to great length to hide things before she leaves her room to go to a meal, or just to leave h er room. She hides everything. Her tv remote, hair brushes, deodorant, anything that’s out, she hides it. She thinks someone will steal her stuff.

Mom is very conscious of where her money goes. Luckily we can refer to the 2 investors that dad hired. They’ve done very well on behalf of my folks. And she still remembers their names when we say “remember Ron or Phil that dad always worked with? That seems to comfort her.