For context, I've known my friend for 8+ years, and stay at his grandmother's place when we both have to work, to make it easier on all of us. Recently, while my friend was at work and I was hanging out in his room, his grandmother came in and started going through his drawers. She kept muttering to herself and whispering, "This is where he usually hides it." When I asked her what she needed, she said, "I just need some money for a while." 

Now, she never actually told me what that money was for and had stolen money from my friend in past occasions, so once she left the room I messaged him to tell him. He was understandably pissed, and called out his grandmother. She tried to play innocent and act like she did nothing wrong, as she tries to do. She started acting extremely passive aggressive towards me, to the point where she came in when my friend was gone and told me that he would be "In big trouble" because I was here without him. Only found out today she needed the money for bills, but had she not been acting the way she did it wouldn't have been an issue.

So reddit, AITA?