I'm going to demand my friend give my stuff back and then avoid them afterwards
Have you asked for your stuff back yet?
I should not have to ask for it back, I told him when I gave it to him to only keep it for a week.
You need to ask him for it back. He could have forgotten the arrangement. There is no reason to end the friendship like this.
He should really honor agreements.
You are right about that. But just ask for the stuff back in a nice way, it is possible he could have just forgotten. There is no need to avoid him.