What does it mean "stand up for oneself"?
In Weekend(2011)

Russell: John has fucked you up, because... he's cheated on you.

Glen: You don't know nothing about me and John. You don't know nothing about how I feel,
about whether he cheated on me or not.
And, for the record, I don't give a shit that he cheated on me.
I give a shit that he was a fucking liar and a faggot and he couldn't stand up for himself.

Russell: Couldn't stand up for...Glen, he was beaten up in a fucking park....because he was gay!

What is the meaning of 'He couldn't stand up for himself' in this context?

Thanks in advance for your reply!

Question

What does it mean "stand up for oneself"?
In Weekend(2011)

Russell: John has fucked you up, because... he's cheated on you.

Glen: You don't know nothing about me and John. You don't know nothing about how I feel,
about whether he cheated on me or not.
And, for the record, I don't give a shit that he cheated on me.
I give a shit that he was a fucking liar and a faggot and he couldn't stand up for himself.

Russell: Couldn't stand up for...Glen, he was beaten up in a fucking park....because he was gay!

What is the meaning of 'He couldn't stand up for himself' in this context?

Thanks in advance for your reply!

Answer

'To stand up for oneself' means to defend one's point of view against someone else, particularly if one is being criticized or perhaps bullied. It is an expression of self-confidence and self-belief.

Answer

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Answer

I think "He couldn't stand up for himself" means "He could not stick to his own values" or "He could not accept his responsibilities".

Answer

Also, it means, don't let others "stand up for you" -- meaning, fight your own battles. In short, don't run away and don't let others fight for you.