My kitty is fat, around 5 years old, and mentally unstable. Will losing weight help her behavior?

I wonder what kind of cat- some breeds are just larger (for example a Maine Coon) 5 years old is in no way shape or form old. I feel by reading your story, with the info given, she may be much happier in a single kitty household. I have a 17 yr old tabby who, for many years had 2 other cats around. She was a loving kitten, lap cat really, and when 1 boy came along she was ok. Then said boy knocked her up and I ended up keeping 1 kitten.It was a constant struggle for her trying to get food and love and my boys were so demanding! She was unhappy :( 9 yrs later her own son came up with diabetes and died 9 months later, the father 2 years after that from other health issues. I was sad to lose my boys but my little cat was much happier. She runs the house again and has no competition for food, attention etc. Perhaps your mother could take her in?