Many towns have a division of Family Services, and many have a senior center with knowledgeable staff who know the local resources. Every state has an Elder Affairs office. There are also many social service agencies that have a guardianship service for elders who cannot take care of themselves, manage their money, etc. Calling the lawyer is an option, but so is calling her primary care physician and reporting an elder in need of services. The physician cannot discuss her care with you or your aunt, but your aunt can talk to (or write to) the physician who is allowed to listen! Your aunt has no legal standing and has limited authority, but she's been a wonderful and caring friend for years. Making two phone calls should put her in touch with the proper agencies who will carry the ball from there.
If the family can get involved and make an appropriate decision, that's great - once Elder Services gets involved, they decide. But if the family's not equipped to help, or not working cooperatively, it's better to have an objective agency involved.
This paranoia is very common in elderly people but the sooner your aunt acts, the better.