Look to the Aramaic-- you know? The language they spoke and used, rather than the language the scriptures were translated into (Greek)
There is a word for brother---- "aho" which rendered into Greek becomes adelphos
There is also a word for cousin-- and it's specific to son of my father's brother. (son of my uncle) "bar dodo."
The term “ben dod" בן דוד, meaning “son of uncle," is modern Hebrew. In ancient Hebrew, there was no word specifically for "cousin." And what's the word "Aho?" Another modern Hebrew word?
Now, a kinsman, or relative, can refer to siblings, cousins, nephews, or uncles, etc. That's why the Septuagint translators, for example, substituted the Hebrew words "אחים" ('âchiem) in Gen. 13:8 with its Greek equivalent "ἀδελφοί" (adelphoi), and "אָח" ('âch) in Gen 14:14 with its Greek equivalent "ἀδελφός" (adelphos) to show kinship between Abraham and Lot, which lineage shows were that of uncle and nephew: "εἶπεν δὲ Αβραμ τῷ Λωτ Μὴ ἔστω μάχη ἀνὰ μέσον ἐμοῦ καὶ σοῦ καὶ ἀνὰ μέσον τῶν ποιμένων μου καὶ ἀνὰ μέσον τῶν ποιμένων σου. ὅτι ἄνθρωποι ἀδελφοὶ ἡμεῖς ἐσμεν." (Gen. 13:8) and "ἀκούσας δὲ Αβραμ ὅτι ᾐχμαλώτευται Λωτ ὁ ἀδελφὸς αὐτοῦ, ἠρίθμησεν τοὺς ἰδίους οἰκογενεῖς αὐτοῦ, τριακοσίους δέκα καὶ ὀκτώ, καὶ κατεδίωξεν ὀπίσω αὐτῶν ἕως Δαν." (Gen. 14:14)
The Septuagint translators substituted the Hebrew word "אָח" ('âch) in Gen. 29:15 with the Greek equivalent "ἀδελφός" (adelphos) to show kinship between Jacob and Laban, which lineage shows were that of uncle and nephew: "Εἶπε δὲ Λάβαν τῷ ᾿Ιακώβ· ὅτι γὰρ ἀδελφός μου εἶ, οὐ δουλεύσεις μοι δωρεάν· ἀπάγγειλόν μοι, τίς ὁ μισθός σου ἐστί;" (Gen. 29:15)
The Septuagint translators substituted the Hebrew word "אחים" ('âchiem) in 1 Chr. 23:21–22 with the Greek equivalent "ἀδελφοὶ" (adelphoi) to show it was kin the daughters of Eleazar married, which lineage shows was their cousins: "καὶ ἀπέθανεν Ελεαζαρ, καὶ οὐκ ἦσαν αὐτῷ υἱοὶ ἀλλ᾽ ἢ θυγατέρες, καὶ ἔλαβον αὐτὰς υἱοὶ Κις ἀδελφοὶ αὐτῶν." (1 Chr. 23:22)
Lastly-- and with this I'm done here..... there is still another Greek word that specifies "cousin" that could/should have been used if that's what was meant-- and it's anepsios -- not adelphios.
If the writer wanted to convey that these were simply cousins and not actual adelphos "brothers' they could have used the word "suggenes" to remove all doubt that these are mere relatives and NOT brothers.
It's used in Luke 1 to describe the relationship between Mary and 'her cousin" Elizabeth. Note that they are not called "sisters" (aldelphos) but suggenes (relatives)-- and we know that they are cousins.
Yes, it's the same Greek word for brothers and sisters--- adelphos. But if the meaning is indeed cousins-- Suggenes is used.
:face palm:
Good God.
Firstly, it's not that kinsmen/relatives are different from siblings. A sibling, cousin, nephew, niece, uncle, aunt, etc., is a kinsman, or relative.
Secondly, the Koine Greek word "συγγενίς" (syngenis) was applied to Elizabeth in Lk. 1:36, and its textbook definitions are "kinswoman, or female relative" and "a fellow countryman." You assert that Elizabeth was Mary of Joseph's cousin, but how do you know its definition "kinswoman, or female relative" and not the other one applies in that verse? If you can show how you know, now present what evidence you have to show that cousin was the type of kinswoman/relative, e.g., sibling, cousin, or aunt, etc., that Elizabeth was to Mary. Without evidence to support that it's just an assumption.
Thirdly, you acknowledge that there's more than one word in the Koine Greek language that can be used to refer to various types of family members, such as cousins, which is why it's weird and asinine that at the same time you essentially argue, "That Koine Greek word that can be used to refer to cousins wouldn't have been used, but rather this Koine Greek word that can also be used to refer to cousins would've been used."
What you're not understanding or accepting is that when referring to one's cousin(s), the use of any of the Koine Greek words that can be used to refer to cousins, which includes "ἀδελφοί" (adelphoi), aptly applies. The only difference between "ἀδελφοί"(adelphoi) and "ἀνεψιός" (anepsios), for example, is that the former doesn't have the direct definition "cousin," or that of any other type of family member, but rather the broad "kinsmen, or relative," though it can still refer to various types of family members, including cousins, indirectly.
Regarding Matt. 13:55/Mk.6:3, the context shows the definition of "ἀδελφοί" (adelphoi) that applies to Jesus's brothers in those verses is "kinsman, or relative," but since that definition can refer to a range of different types of family members, e.g., siblings, cousins, nephews, or uncles, etc., it means we can't determine from the definition itself what type of family members Jesus's brothers (kinsmen/relatives) were to Him. That's why one needs more information to go on to find that out. You assert that siblings were the type of family members Jesus's brothers (kinsmen/relatives) were to Him, but when I asked you to provide information to support that you didn't give any. Instead, you just said you assume that because there's no reason not to. Well, I've explained the reason not to, and without evidence to support your assumption it remains just that.
I, however, have actually given something (scriptural verses and early Christian testimonies), which is better than your nothing, to show those kinsmen/relatives of Jesus were the sons of Jesus's uncle, and thus His cousins. Another thing you don't do is actually show why that evidence of mine doesn't show what I claim it does.