What Causes Weight Gain Along With Headache And Gastritis Post Heart Attack?

hello my mom is 68 years old she had a heart attack a year and 4 months ago she had 4 stents put in 2 on the right 2 on the left. the doctor said after 3 months she would be as good as new well she hasn t been. she weighed 145 pounds at the time of her heart attack and now she is 212. she has gain weight her stomach is always swollen and now she is on oxygen 24/7 she cant walk without gasping for air. before her heart attack she never had any problems with weight gain or breathing and she did everything herself she has been diagnosed in the past with rhemotoid arthritis and fibromyalgia and she also has congestive heart failure. all she does now is sit in a chair not being able to do anything its a task to even take a shower. she has had an echo, cat scans, mri, bloodwork everything is coming back normal. her heart doctor is telling her to lose weight but that s the thing she doesn t hardly eat anything to have this weight on her. she is getting very weak its hard for her to walk around and she tells us if she doesn t get help she is going to die. every place we take her they look at her like there is nothing wrong but there is it has to be something that they are over looking she feels sick everyday when she wakes up and she has headaches everyday she has a lot of gas on her stomach all the time and she belches a lot.