What type of manipulation is this?

I didn’t know where else to post this. Me and my ex broke up recently but we’ve still been talking. Lately his behavior has just been unhinged as fuck, and idk what the reason is. I’ve started to accept our breakup and feel better. So the other night he got drunk and was texting me talking about some personal issues in his life, I was there for him and listening to him. He never opens up like that unless he’s had a few drinks. Then mid convo he starts thinking I was one of his other guy friends and texting me like I’m him. I was responding confused saying “what are you talking about? It’s me.” Then after this he started questioning how I know that friend of his and started accusing me of being with him sexually. He threatened to block me and I was like whatever go ahead. I obviously know he’s drunk so I just didn’t even put any energy into it, I told him “just read these texts in the morning, I’ll talk to you tomorrow.” Then he switches up AGAIN and thought he was talking to a different friend about ME. He was saying how much he misses me, saying I’m different and I made him feel something, etc. I’m just going along because I genuinely didn’t know what to say. Then he comes back AGAIN acting like he’s talking to me again. Completely changed the topic. Started talking about something else. Started saying he wishes I was there and whatever. There’s no way he actually thought he was talking to 3 different people right? I’m sorry but even when I get drunk I know who I’m texting. So my question is what was the point in him doing that? To get my attention?