One thing I have observed from my time among Egyptians (and Assyrians/Syriacs, Maronites, and other Middle Eastern Christian people) is that they will very often refer to one another by familial terms, even though they are not literally genetically related. The older women in the parish are everyone's "aunt", and the older men are everyone's "uncle". Men around the same age are "brothers", and everyone of any age is "my beloved" (habibi) -- especially if they're asking you for some favor or trying to convince you of something.
It is also standard that the priest is "Abouna", literally "our father" (as in the patriarch/leader of the congregation; this is a different form of the noun than is used in the Lord's prayer, where we say "Abana" in Arabic:
"Abana ilathy fi as-samawat..."), and in the Egyptian tradition the wife of the priest is "Tasoni". Tasoni is Coptic for sister. Tamav, the Coptic word for mother, is apparently reserved for abbesses, like the famous modern saint Tamav Irini (Mother Irene), abbess of the convent of Abu Seifein/St. Philopateer Mercurius in Old Cairo.
So it doesn't really surprise me that the Bible uses these sorts of terms and it has still not been the case until modern times that anyone believed that Jesus had brothers or sisters from St. Mary and St. Joseph. This is just how people in that part of the world talk, even until today. I never had so many brothers and sisters and aunts and uncles and fathers and mothers (etc.) until I began meeting Middle Eastern Christians!
The fact remains that the belief that St. Mary's virginity was not kept intact after the birth of Christ our Lord is a modern belief not in line with the mind of the early Church on this matter, but instead born of the logical wanderings in the minds of those who cannot read the scriptures along with the same early Church, as we have seen in this thread.
To substantiate and correct this, let us read what our father St. John Chrysostom
has to say on the matter (a saint in common in the Eastern and Oriental Orthodox, to the best of my recollection also with the Eastern and Western Catholics...so, no lightweight in any fashion):
"And took unto him Mary his wife." Do you see how continually the evangelist uses this word, not willing that that mystery should be disclosed as yet, and annihilating that evil suspicion?
"And when he had taken her, he knew her not, till she had brought forth her first-born Son." He has here used the word "
till", not that you should suspect that afterwards he did know her, but to inform you that before the birth the Virgin was wholly untouched by man. But why then, it may be said, has he used the word,
"till"? Because it is usual in Scripture often to do this, and to use this expression without reference to limited times. For so with respect to the ark likewise, it is said,
"The raven returned not till the earth was dried up." Genesis 8:7 And yet it did not return even after that time. And when discoursing also of God, the Scripture says,
"From age until age You are," not as fixing limits in this case. And again when it is preaching the Gospel beforehand, and saying,
"In his days shall righteousness flourish, and abundance of peace, till the moon be taken away," it does not set a limit to this fair part of creation. So then here likewise, it uses the word
"till," to make certain what was before the birth, but as to what follows, it leaves you to make the inference. Thus, what it was necessary for you to learn of Him, this He Himself has said; that the Virgin was untouched by man until the birth; but that which both was seen to be a consequence of the former statement, and was acknowledged, this in its turn he leaves for you to perceive; namely, that not even after this, she having so become a mother, and having been counted worthy of a new sort of travail, and a child-bearing so strange, could that righteous man ever have endured to know her. For if he had known her, and had kept her in the place of a wife, how is it that our Lord
John 19:27 commits her, as unprotected, and having no one, to His disciple, and commands him to take her to his own home?
How then, one may say, are James and the others called His brethren? In the same kind of way as Joseph himself was supposed to be husband of Mary. For many were the veils provided, that the birth, being such as it was, might be for a time screened. Wherefore even John so called them, saying,
"For neither did His brethren believe in Him."