How can I help my plant?

It's never been easy with this one. I'm watering every 4 to 5 weeks, last time was 2 weeks ago. Usually I put enough water in the pot for the soil to be soaking wet. Then I let everything dry out and when I remember having a plant, I will do it all again. It's right next to a window, so it gets sunlight during daytimes (if you could say that during winter). The leaves have always been somewhat curled up and got brown before, but I could handle that by increasing the dry periods. Now it's becoming black all around and idk what's wrong this time…any help is appreciated 🤝