On my macbook it shows my brother called from his ipad, i picked up thinking it was him but I answer, complete silence and then I see his ipad start ringing showing I called

So I was trying to look up some things on my Macbook, and all of a sudden I get a Facetime audio call that shows on my macbook from my little brother on his Ipad. I pick up thinking it was him just playing around but the call was silent for about 2 seconds and then turns out his Ipad was in my room, nobody using it and it starts ringing showing I called him. Why did this happen and has this happened to anyone else?