That's all well and good, but Jews of the time were identified as "son of" not brother of. There is no doubt in my mind that these others were close to the Lord growing up, it is very possible that they were raised by the Holy Family and were referred to as brothers. But the fact still remains that they are not identified as the children of Mary because that is untrue. If they were, Jesus would not have had the option of leaving His Mother in the care of John.