Let me tell you the story of two brothers:
Brother #1: overweight, even after three bypass surgeries, little was done to change his diet and exercise. He remained very heavy. Never smoked, but just heavy. Was heavy as a child as well. For the last 4 years, doctor never did blood tests to check on cholesterol levels or drug levels in bloodstream. Brother #1 becomes lethargic, ashy-skinned, and pretty close to dying. One day, out of the blue (presumably during Bro. #1's last weeks), doc decides to do a full blood workup. results come back: lethal, not just toxic, but LETHAL levels of meds in bloodstream. Doc immediately cuts meds back to reasonable levels. Bro. #1's color returns, energy improves... you get the idea. Unfortunately, heart couldn't take sudden cut in meds and Bro. #1 passes away after a few months. (some of us believe that at least his last few months were decent... he got to work in the garden again). All of this within ten years of his first surgery.
Brother #2: Roughly same age as brother #1, a year or so younger. Not an exercise nut, but definitely more active around the house. Also does not smoke. Goes in for angioplasty, it fails, so he's rushed in for a double bypass. Docs believed he wouldn't make it through first night, but he does (those gutsy Swiss genes, i tell ya). Goes on with life, but with some changes: diet, walking daily, and regular doctor visits. His general physician makes him come in every three months. The cardiologist is once a year. During each and every visit, blood is taken for a full workup. Every three months. No if's, and's or but's. He eats red meat roughly once a month, chicken and fish the rest of the time. He cooks his own soup for lunches. Barley and all sorts of stuff. He still walks a little, but with a bum achilles tendon (injured it) and bad knees, he's slower than he used to be. it's been 18 years since that surgery. Typically, heart patients need at least a second surgery within the first ten years. He's never had to. He's now 79 years old. He'll be 80 in November. Trust me, he'll make it.
Brother #1 was one of my uncles. He was a wonderful man and he passed away far too soon. He had the chance to make a lot of changes, but never did. Maybe his doctor wasn't informed enough. if so, shame on that doctor. A lot of factors went into his situation. but they don't have to happen to your mother, or anyone else. She needs to start making changes now, before it gets to bypass surgery. She can reduce her risk factors before she gets any worse. medication [heavily monitored], a change in diet, and moderate exercise. If your father is willing to make the dietary changes and exercise with her, it'll make it a lot easier on her.
My mom formed the opinion: if it's good for your father ,it's good for you. well, when you feed a 15 year old a low cholesterol diet, it may not always be the best (I was tested at 22 for cholesterol... total was 88... my dad's doctor had him relay this message to me: eat more cheeseburgers! Which I did, happily), but if at least the two adults stick to the dietary changes, things will be okay.
Okay... I think I said enough... I really need to do something else... argh!