My Ex Is Unwilling To Pay The Security Deposit Deposition Letter

Location: Wisconsin I lived in an apartment for 4 years I paid for the security deposit out of my own pocket I paid for everything for multiple years I lived with my ex who couldn't pay for anything after 3 months of living there had to move back in with his parents about a year later you decided that he wanted to live with me for about a year and then I lived there for one year after that there's some differences in the time it's not exact but... We both went through some pretty traumatic stuff, he moved out a year before the lease ended little bit more. So I asked him to sign the lease renewal he did and then I lived there for one more year I got a notice to vacate and then I moved out, a month before I moved out I got an email notifying me that he wished to be removed from the lease, sorry to sign some paperwork releasing him from the lease (I was planning on doing this earlier by submitting some pay stubs but I kept procrastinating it) i got my security letter back at the mail and it has both of our names on it, and he is unwilling to sign it if we were to meet in person, because we both went through some traumatic stuff, there's an option where I could mail it to him he could sign it and then mail it back but then he's demanding that he's entitled to like a quarter of it, "due to the mental exhaustion of resigning the lease"

Some other context is, he lives with his parents of 22 so if I were to show up on his doorstep to get him to sign it his mom would call the police, he paid none of the security deposit whatsoever it was a gift from my parents that I wanted to give back to them, and he paid maybe for half a four months rent because that was the only time he had a job before he decided to move out, that was the only time he helped with anything, I can add more context in the comments but I think that covers everything. I'm trying to figure out if taking him to court is an option to get him to sign it or if there's somewhere I can get the police involved. I don't know I kind of just want this dealt with