How terrible would I be to suggest that my mother loses weight?

My mom is 5’5 and over 200 pounds. I don’t know the exact weight. She may be 300. I don’t ask because that’s rude. But she’s definitely at least obese. She has many joint problems and she’s currently dealing with insane swelling. She breathes SO LOUD. The whole time I’m around her, she seriously sounds like Darth Vader. It’s clear her health is suffering. I don’t think losing weight will solve all of her health problems, but I definitely think it will help tremendously. She can barely walk and I think it will help with the swelling and her mobility. She can barely fit in her knee and back braces and she can’t fit in shoes anymore hardly.

I want to suggest that she loses weight to help with her health. I just don’t want to be an ass. I love my mom and I definitely don’t want to hurt her feelings, but she needs to make changes. She knows she’s at an unhealthy weight. She called herself fat this morning. I want to suggest it so she knows I’d help her and support her, but I don’t know how. I just recently lost 50 pounds so I think I can give her helpful advice and be able to relate. I don’t know if it’s a good idea or not though.