Is the questioner considered deficient in caring for her elderly and ill mother if her visits are limited to what her husband permits, to avoid problems with her brother, and due to her inability to serve her alone?

There is no harm in visiting one's mother without staying with her for several days, and this is not considered a shortcoming, especially if there is someone to care for her. However, if the mother is in need of care and there is no one to look after her, then this care becomes an obligation upon all of her children. It is recommended to be mindful of potential problems and to strive for harmony and affection among relatives.