Motive, bidding,cause, morality, 'in best interests'

To do someone's bidding when it is not in their best interests, on the contrary,and would be in the opposite interests or detriment of that individual and those around them? Can that be right? Of course it's not. If your Father brother or sister tells you to take actions that damage him or her it would clearly be wrong according to law. That is why it would be wrong in law in England to assist someone's death or suicide (to use recent examples of a close relative aiding and abetting euthanasia cases) 'In best interests' 'Morality' Subjective terms/words defined in law....