Thanks for writing.
Someone who knows where she lives needs to call the police in her area and have her picked up on a Baker Act. DO NOT wait - if she is hearing voices telling her to kill someone - SHE WILL ACT ON THOSE.
Call the police and have them go pick her up - she will be placed on a hold in a hospital and they will give her the right medication to make the voices go away.
DO NOT IGNORE THIS. That invalid woman is in a life-threatening situation and if she dies, you will be partly responsible. She could also kill the child.
CALL THE POLICE NOW.
Social services will find help for them until this woman comes home in 3 or 4 days.