I’m pretty sure this verse has been explained many times in this forum, Matthew 1 the word until in Greek is ambiguous as to when the event ceases. In any case the primary objective of the Gospel writer was to say Mary and Joseph never has sex in that period of time, so we can know a Virgin was with child.
The word until is used in Matthew 28:20 to refer to something that continues passed what we would normally think would signify the end of an action:
“And behold, I am with you always, **until **the end of the age.”-
Concerning the brothers of the Lord notice the spelling of the name “Joses” only appears 3 times in the New testament and all in Mark’s gospel (Mk 6:3, 15:40, 15:47) and the pair Joses and James mentioned twice together:
Is he not the carpenter, the son of Mary, and the brother of James and Joses and Judas and Simon?–Mark 6:3
There were also women looking on from a distance. Among them were Mary Magdalene, Mary the mother of the younger James and of Joses, and Salome–Mark 15:40
So James and Joses are sons of A MARY, but not Mary, the Mother of Jesus otherwise the Gospel writer would have said “Mary, the mother of the Lord” or “Mary his mother” or “Mary, the mother of Jesus” as the Gospels do when referring to Mary.
Brothers can refer to close relatives, not necessarily only sons of the some mother for instance Mary has a ‘sister’ named Mary:
“Standing by the cross of Jesus were his mother and his mother’s sister, Mary the wife of Clopas, and Mary of Magdala.”–John 19:25
This Mary was in some way Jesus’ aunt, and she was the mother of James and Joseph, she was married to Alphaeus/Clophas (which is the same name)
Now the Judas and Simon mentioned in Mark 6:3 are also likely sons of Mary wife of Clophas. According to the Church Father St Papias the Bishop of Hierapolis (Pamukkale, Turkey) and disciple of ST John, wrote around the year 100, and all 4 of these names were listed as being sons of an aunt of the Lord, Mary wife of Clophas.
“(1.) Mary the mother of the Lord; (2.)
Mary the wife of Cleophas or Alphæus, who was the mother of James the bishop and apostle, and of Simon and Thaddeus, and of one Joseph; (3.) Mary Salome, wife of Zebedee, mother of John the evangelist and James; (4.) Mary Magdalene. These four are found in the Gospel.** James and Judas and Joseph were sons of an aunt (2) of the Lord’s.** James also and John were sons of another aunt (3) of the Lord’s. Mary (2), mother of James the Less and Joseph, wife of Alphæus was the sister of Mary the mother of the Lord, whom John names of Cleophas, either from her father or from the family of the clan, or for some other reason.[now we know they are linguistically the same name] Mary Salome (3) is called Salome either from her husband or her village. Some affirm that she is the same as Mary of Cleophas, because she had two husbands.”
Matthew’s Gospel spells the name “Joses” as Joseph for these “brothers,” and Papias chose this spelling.
Notice Jesus has a brother named James that is an apostle in Jerusalem:
Then after three years I went up to Jerusalem to confer with Cephas and remained with him for fifteen days. But I did not see any other of the
apostles, only James the brother of the Lord.–Galatians 1:19
St Paul is most likely using the word apostle to refer to the 12, which would make James the brother of the Lord one of the 12, and one James is Alpheus’ son, other other Zebedee’s. I think this is James, brother of Joses, son of Alpheus and his wife Mary. But in either case James’ is called “brother of the Lord” though he is the son another mother and father.
This is a long complicated puzzle really to see that Jesus’ brothers were his relatives. Its an ancient tradition that Mary had no other biological children, but she did have spiritual children (eg the beloved in John 19:26, Rev 12:17) Luke 2:7 mentions Jesus as her “firstborn son,” this verse Church Father used to show Mary as our spiritual mother.
BTW a first born son can be an only biological son also since a tomb of a Jewish woman in Egypt was found written in Greek from the 1st century stating she died giving birth to her “firstborn child”
catholic.com/thisrock/1990/9001fea2.asp