My partner is having a manic episode or something and I’m scared

My partner has been experiencing a manic episode or something similar since about 1am, and it’s scaring me and I don’t know what to do. He’s been ranting about numbers and parallels and how we’re all missing the signs. He called a bunch of people in his contact list at 3am and worked himself into a panic attack convinced that he, his brother, his brother’s dog (?) and his dad were all going to die of heart attacks today. We were walking to the car and he dropped into the mud and grass and started doing the worm, swear to God. He’s never done anything like that before. I’ve been crying all day because I’ve never seen him like this and it’s really scaring me. I’ve never experienced a mental health crisis like this with anyone and it’s scary how he’s saying such crazy things and acting like they’re normal. He keeps saying “you’ll understand one day” and “you’re crazy until you’re proven right”. I dropped him off at his mom’s house because she’s dealt with this with his brother apparently, and I’m not mentally equipped to help him through this myself. I think this is brought on by lack of sleep, he hasn’t slept much at all in the last week or so. I guess I just need someone to tell me he’ll be okay…