Nairobi, Aug. 10 -- What happens when an ageing parent loses the ability to make important financial decisions? Across Kenya, the assumption is that a spouse or an adult child can step in, operate the bank accounts, manage property or run the business.

Under Kenyan law, that is not only unlawful, but it can leave families in a legal bind.

Relatives do not automatically acquire the authority to manage the affairs of an adult who has lost mental capacity, lawyers say. Instead, they should petition the High Court for the appointment of a manager under the Mental Health Act.

"The family cannot appoint itself manager of that person's affairs. Nobody, not a spouse and not even the eldest child, can lawfully sign for that person simply becaus...