So do trades unionists.
So do Christian monks.
So your point is?
Then there are these, for example.
For whoever does the will of God, he is my brother and sister and mother Mark 3:35
For he who sanctifies and those who are sanctified all have one source. That is why he is not ashamed to call them brothers Hebrews 2:11
We know that we have passed out of death into life, because we love the brothers. Whoever does not love abides in death 1 John 3:14
Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God Hebrews 3:12
Paul, an apostle—not from men nor through man, but through Jesus Christ and God the Father, who raised him from the dead— and all the brothers who are with me, To the churches of Galatia: ... Galatians 1:1-24
Now concerning spiritual gifts, brothers, I do not want you to be uninformed. ... 1 Corinthians 12:1-31
And the King will answer them, ‘Truly, I say to you, as you did it to one of the least of these my brothers, you did it to me.’ Matthew 25:40