He heard the old lie about him and kept silent.
Yusuf holds back his reply
When the bowl was found, the brothers said: if he stole, a brother of his stole before, meaning Yusuf, to distance themselves. Ibn Kathir says Yusuf kept his reply to himself and did not say it aloud: you are in a worse position, and Allah knows best what you describe.
In the family group, someone brings up an old, false story about you. You know the truth. You could send the long, angry reply. Sometimes the strongest answer is the one you keep inside and leave with Allah.
If someone lies about me, I must correct it immediately.
Not every unfair remark needs my answer; Allah knows the truth of it.
Next time someone says something unfair, wait before replying, and say inside: Allah knows best.