People with a bad heart are not suitable for excessively intense activities. Go for a walk in the park every morning or evening, and it is easier to lose weight by going out for more activities. There are some fitness videos for the elderly on the Internet, which are very gentle and simple. You can do it at home. You can learn to feed your mother first and take her to exercise every day. Eating less than three meals is not a healthy performance. A reasonable diet can ensure a balanced metabolism, so that the elderly can eat more fruits and vegetables, which is beneficial to metabolism.
You can eat some health care products for the elderly if necessary.
In view of your mother's physical condition, it is not safe to lose weight quickly. Do more activities, keep an optimistic attitude, and let nature take its course.