expression
even siblings become strangers
Proverb meaning that even close family relationships can grow distant over time, especially after siblings establish their own families.
兄弟は他人の始まりというから、たまには連絡を取り合ったほうがいい。
They say even siblings become strangers, so it's good to keep in touch once in a while.
A Japanese proverb; the exact origin is uncertain, but it reflects a common observation about family relationships.