Matthew 12:46-50
46 While He was still talking to the multitudes, behold, His mother and brothers stood outside, seeking to speak with Him. 47 Then one said to Him, “Look, Your mother and Your brothers are standing outside, seeking to speak with You.” 48 But He answered and said to the one who told Him, “Who is My mother and who are My brothers?” 49 And He stretched out His hand toward His disciples and said, “Here are My mother and My brothers! 50 For whoever does the will of My Father in heaven is My brother and sister and mother.”
Hmm... Jesus didn't include his birth mother and siblings in His statement. It could be inferred, at this time, they did not yet believe in Him.
His birth mother did not yet believe in Him?
Surely you can’t serious when you say this.
As for your interpretation meaning that Jesus’ words to the crowd might mean that He automatically excludes His mother; actually He is calling everyman to the level of faith and faith-living exemplified by His mother.
Of course, I fully understand that this is a YOPIOS situtation.
Jesus is even more explicit about this fact when He instructs those in his own synagogue...
And when the sabbath day was come, he began to teach in the synagogue: and many hearing him were astonished, saying, From whence hath this man these things? and what wisdom is this which is given unto him, that even such mighty works are wrought by his hands? Is not this the carpenter, the son of Mary, the brother of James, and Joses, and of Juda, and Simon? and are not his sisters here with us? And they were offended at him. But Jesus, said unto them, A prophet is not without honour, but in his own country, and among his own kin, and in his own house." -- Mark 6:1-4"And he went out from thence, and came into his own country; and his disciples follow him.
Even those mentioned from His own house, his mother and his brothers and sisters, did not yet recognize Him as God.