Like I said, there are multiple passages that discuss Jesus’ brothers, as well as “who” the individual families they belong to. Here are the main verses I used to cross-reference with each other to come to the conclusion - Biblically - that the “adelphos” of Jesus are His half-brothers. But you have to examine them - as a whole - rather than individually. Otherwise, if you critique each individual verse with a preconceived religious belief, you won’t realize how your interpretation of that individual verse causes cross-referencing problems with other verses. I would suggest physically writing out each individual family unit pertaining to each verse:
Matthew 10:3; 12:46-50; 13:46-50; 20:20; 27:56; Mark 10:35; 15:40,47; 16:1; Luke 1:36; John 2:12; 6:42; 7:3-5; 19:25-27; Acts 1:13-14; 12:2; 1 Corinthians 15:3-8; Galatians 1:19; 2:9; James 1:1; Jude 1:1; Psalm 69:8
For Mt 10:3, I think that you want 10:2. Also, Mt 13:46-50 seems to be a mistaken reduplication from 12:46-50.
A. Mt 12:46-50 and Jn 2:12 and 7:3-5 and Ac 1:14 use αδελφοι for people with whom Jesus had a close association, presumably for members of his household and/or wider family. On the other hand, 1 Co 15:6 (like many other verses in the NT) uses αδελφοι very broadly, for Christian brethren. These verses show us that αδελφος was used in a variety of ways, as was normal in Greek, and so we cannot logically assume that αδελφος = συναιμος.
B. Mt 20:20 and 27:56 specify that the αδελφοι who were sons of Zebedee in Mt 10:3/Mk10:35/Ac 12:2 had the same mother. On the other hand, Ac 7:13 uses αδελφοι for a group of 12 people of whom only 2 had the same mother. These verses show us that αδελφος was used in a variety of ways, as was normal in Greek, and so we cannot logically assume that αδελφος = συναιμος.
C. Lk 1:36 refers to Mary’s συγγενης (as does 1:58, with the plural). While Ps 69:8 uses αδελφοι and 'υιοι της μητρος as synonyms, Romans 9:3 uses αδελφοι and συγγενεις as synonyms. These verses show us that αδελφος was used in a variety of ways, as was normal in Greek, and that the fields of denotation of συγγενης and αδελφος overlapped.
D. Jn 6:42 shows that the Jews thought that Jesus was Joseph’s 'υιος, which is not particularly relevant.
E. Jn 19:25-27 shows Jesus using typically-familial terms (μητηρ and 'υιος) in a broad fashion, as was normal in Greek. It also shows Jesus passing his mother into the care of a male outside of his family, which suggests that there was no close male relative to perform that role.
F. Mk 15:40, 47, and 16:1, and Mt 27:56 refer to Mary the mother of James the Less and of Joses (Ιωσης). There is no reason to presume that this Mary is the mother of Jesus, since a/ all of these were quite common names from the period, b/ that other group (Jesus’ apparent household/associates) includes not only a Ιακωβος and a Ιωσης but also a Ιουδας and a Σιμων (Mk 6:3, Mt 13:55), which would make omitting half of them very strange
especially since it is expressed that way in both gospels, c/
in neither gospel is the mother of James and Joses identified as the mother of Jesus, the omission of which would be quite bizarre, and d/ there is no mention of that Mary being the mother of John, despite Jn 19:25-7. That is, in all probability, another Mary.
(Also, this is James the Less, not the James of Ac 15:13, one of the leaders in Jerusalem, the one mentioned in Gal 1:19 and 2:9, who most probably was the James in Mk 6:3 and Mt 13:55.)
G. We do have an extra-biblical historical source, the
Protoevangelium of James, which claims that Mary had no other children. Since that text was written within one lifetime of Jesus’ ministry, if its claim were false, we could reasonably expect C2nd or 3rd criticisms of its historical inaccuracy but we have neither those nor records of same (despite having copious records of such criticisms on other scores, e.g. Epiphanius’
Panarion).
H. We have no record whatsoever of the subsequent lineage of Jesus’ brothers. Given the nature of eastern Mediterranean cultures at the time, their ideas of inheritance, and Jesus’ status within the early Church, his nephews, grand-nephews etc would have been celebrities. Instead, there is just nothing, and this is coherent with the theory that Jesus gave his mother into John’s care because they had all died.
I. The Orthodox have been reading these texts in their own language, with minute scrutiny, without any dogma telling them what to believe, for two thousand years, and the majority consensus from them is that there is no evidence of Mary having had other children.
Just to reiterate, none of this is dogma for me, either. However, on a linguistic basis, there is no clear demonstration that the αδελφοι of Jesus were Mary’s children, and, on a historical basis, there is no evidence of but instead attestation against any such children having existed. I cannot disagree with that unless I get hold of a time machine, go back, and take DNA samples.