Yep, that's why we all are in this hobby, lol.
I'm a little worried for one of the bettas I'm keeping. He is changing colors and isn't as active as the two others.
That's too bad. With the neglect from owners and the fact they would be upset if you tried to improve their habitat, there isn't much you can do. You might try adding a small amount of non-iodized salt to the water, like a tsp. per gallon.