How to deal with aging mother with sociopathic behavior that is at risk to self and others

It sounds like your mother may need to consider a Durable and Medical Power of Attorney to allow you and your brother to handle her affairs and potential medical needs. This is essentially a document that would allow you to pay her bills, direct her medical care, and act on her behalf. As long as she is able to understand what is happening, this is probably going to be your best choice for the continued care of your mother. If she is unwilling to sign power of attorney documents, you may need to seek guardianship over your mother. This is a quite lengthy process wherein the court appoints someone (usually a family member) to take care of the physical and financial needs of an elderly or disabled person. For more information about guarianship, please go here: http://texasguardianship.org/guardianship-information/guardianship-basics/guardianship-process-2/