That's officially known as "morbid obesity."
I remember a story a couple of years back, an ambulance responded to a call of an asthma attack to find a woman in her 40's, about 1,000 lbs, and she was FUSED to the couch. Her skin literally grew into the fabric. (She later died.)
She had not gotten up in YEARS. Do you know what that means? It means she didn't get up to go to the bathroom. Or shower. And she had a family, an entire family of people who were enabling her. Apparently, she broke her ankle, and she just never got up after that.
The paramedics said it stunk to high hell.
How does a family allow that to happen?