"Is that you in the video?" phishing attempt

Hello everyone, a hacker hacked my friend's FB account and sent me a message like this with supposedly a video of me "Jonathan, is that you in the video?" but my friend was able to recover his Facebook account thankfully. However, I have a question: how could my friend have had his Facebook account hacked? Because he told me that a friend of his sent him this fake video and my friend clicked on it and apparently got hacked. How is it possible to get hacked just by doing that? I clicked on this fake video and yet I didn't get hacked, that's what I don't understand. And then it redirected me to a FB page, a group actually, and there was a post and in that post, there was a link, and I clicked on the link, which redirected me to a fake Facebook site (phishing), and I didn't enter my login details because I'm not stupid enough to fall for a phishing attempt.