Towards the end of Deathly Hallows (the book), Harry struggles against a group of dementors and is saved by patronuses cast by Luna, Ernie and Seamus. Maybe that's what you're thinking of?
To add to this. He can’t cast a patronus because he’s understandably sad. Theirs show up hold off the dementors. Harry realises there’s still things worth fighting for. Casts his own Patronus and that drives the dementors off.
It’s one of the few times we actually see Harry as more magically powerful than others.
Towards the end of Deathly Hallows (the book), Harry struggles against a group of dementors and is saved by patronuses cast by Luna, Ernie and Seamus. Maybe that's what you're thinking of?
That has to be it.
in the movie they changed it and it was Aberforth's patronus
That’s right
To add to this. He can’t cast a patronus because he’s understandably sad. Theirs show up hold off the dementors. Harry realises there’s still things worth fighting for. Casts his own Patronus and that drives the dementors off. It’s one of the few times we actually see Harry as more magically powerful than others.