I have a friend who is intellectually disabled. She reads at about a second-grade level. If I am unable to help her can a lawyer?
The question does not appear to be about whether the person is physically capable but whether the person has the mental competence to make decisions in their own best interest, If an adult (meaning over the age of 19 years in British Columbia, Canada) is not able to care for themselves eg to not be able to make decisions on their own without help, then there are several options available in British Columbia for another adult to make decisions for their care and benefit.
If the person who has a mental disability still has sufficient ability to make a decision (ask their physician for a written opinion) then it is possible that they could appoint a representative(s) under the Representation Act to make financial as well as health decisions for them. To protect against allegations of theft or embezzlement, etc, it would be prudent that a different person be appointed as a “Monitor” so there is someone to whom the Representative is accountable.
If the person with the mental disability does not have sufficient decision-making ability then a person can apply under the Patients Property Act to the Supreme Court of British Columbia to become a “Committee” of the disabled person.
Any of us at any age can suffer a mental disability whether temporary or permanent, whether by illness, accident or otherwise. It is prudent for all of us to do life as well.