I ruined my brother's new boots?
How did they get ruined?
I stepped into a mud puddle and they tore.
You should be more careful with other people's possessions. You should replace his boots as an apology.
I'll get him another pair. I'm just glad my boots and shoes are safe.
That is good you are owning up to what happened. You should make sure you tell him the truth and replace it exactly.