I'm going to accuse my brother of stealing
Are you sure your brother stole something?
I video recorded everything with my tablet and analysed the images
Well if the pictures show that it was your brother, then I would confront him. It is not okay to steal, and he should know that.
It's his word against mine, he can't prove anything.
If you have proof it was him that stole then he can't deny it. Maybe after you confront him you will find a good reason for his thievery that will allow you to forgive him.