Friend Now Wants To Sue Me Out Of Jealousy

My best friend helped me through a tough time in my life. Constantly offered help when he knew I needed it and was vulnerable. I had a lot of debt and was working 2 jobs, dealt with an abusive ex partner, had moved away from all family previously. Our friendship was always platonic, at least it seemed to be from both sides. Knew my family as well.

I got money from an inheritance and paid off my debt and a big chunk of the money I owed him. I offered to pay more and pay the rest of my debt later but he didn't accept it. Constantly told me he didn't care if I paid him back or when. I'm still rebuilding my credit so I can't get a personal loan at the moment. He said he wasn't in a rush and didn't care if I ever paid it back. I even offered to pay in monthly payments and he said no if I pay he wants a lump sum if possible but again no rush even if it takes me years.

He had sold me a car as well but the car he claimed had a new engine and was in reliable condition required about 4 grand in repairs.

Our friendship continued as normal until I started dating someone he didn't like. I should have seen the red flags before but I didn't have any friends and thought he was a good person. But he was always verbally abusive whenever I didn't take his advice or did something he didn't like. So when I told him I was dating he flipped out and made conditions for our friendship like only texting once a week and on holidays. Said he would never visit unless I was single again.

He had a habit of sending serial texts in the middle of the night when drunk. Blamed his brother at first but I know it was him. Recently serial texted and cussed out my mom and was serial texting me as well, mostly gibberish and incoherent texts. Last night in the middle of the night texted me to pay him back or he would get lawyers involved and that he had bank accounts and texts. Again, the texts he has is everything I explained above. Could he really sue me? I'm also concerned about him showing up or causing trouble. He lives in another state but he has had a restraining order before for getting into a physical altercation with his ex's new partner.