Guardianship trumps all other documents, since it is a court order. Any changes have to be ordered by the Judge in Surrogate's Court. No other way, sorry. Judges are very reluctant to remove spousal rights, so brother would have to show serious cause to remove a Guardian.
Your post title states that "one parent has POA and guardianship" yet you also state that your brother has a health care proxy.
Does your father have guardianship but your brother holds the health care proxy? And your mother is living with your brother, not your father, even though he is her guardian?
What exactly is it that you want to "take away", and why? What are the grounds for challenging the guardianship and/or the health care proxy?
More information and clarification is needed to respond to your inquiry.
Does your father have guardianship but your brother holds the health care proxy? And your mother is living with your brother, not your father, even though he is her guardian?
What exactly is it that you want to "take away", and why? What are the grounds for challenging the guardianship and/or the health care proxy?
More information and clarification is needed to respond to your inquiry.