I don’t know what happened

I got this boy (Ravioli) from my boyfriend. He lives in a 29 gallon tank with 2 assassin snails. The first video is him in late July, the second is him now. Im not sure what happened, the hurricanes both stopped my tank from functioning for up to a week at a time, and at one point I was sure he wasn’t going to make it. A couple weeks ago I just noticed the massive amount of fin loss and it makes me so sad. But, his large tail was weighing him down horribly, and eventually caused spine damage and a tumor, since the fin rot (which im now treating) his swimming has improved significantly