Interesting that the Lord gave Mary's care, not to His own family members but to one of His diciples. Evidences as well that Mary needed the protection and care. If she was as powerful as is spoken of her now she is departed then I would assume she could have been powerful enough to take care of herself then. Obvious Jesus recognized clearly she had no power and put her in the care of one He trusted would do so.
Which is why she lived in the care of his ‘brothers’? ;)
Of course she needed care. She would have been an aged widow at that point in time, and I don’t know about you but families looked after each other back then.