Sorry to hear about your mom. Glad you're determined to take steps in the right direction. I dropped from 6'3 300 lbs to 175 lbs (bulking now at 185), so I've been there.
So let's get right down to business.
The most important thing, especially considering your liver condition, is to stay the fucking hell away from sugar. Do not drink soda, fruit juice, energy drinks, or alcohol. Whole fruit is okay in moderation, like berries.
You do not need to eliminate carbs from your diet, and it's very difficult anyway since you often have to prepare all of your own meals if you want to go keto. It is *not* necessary to do this, and it is not for everyone. I've done it in one month stints and I've lost significant weight in the process, but I've also had complications from it when I haven't been strict about my fiber intake. Even one day of missing my fiber quota when I forgot to buy some leafy greens to go with my dinner and I had really bad stuff happen to my bowels. If you can manage it, it can be a useful tool since it brings your appetite down to zero without catabolizing your muscles, but don't dwell on it if you can't.
That said, you want to aim for a diet that satisfies you without being high in calorie. That means high protein and fiber. Meat, leafy greens and other healthy veggies, and whole fruit (in moderation) are at the core of this. You do not need to cut carbs out; by all means, have a taco. But make the taco yourself and don't go to Taco Bell where the "meat" is 40% beef and 60% grain filler, cooked in rancid vegetable oil. An option for that taco, too, is to make it with a low carb tortilla that has a bunch of fiber in it. That was one of my go-tos.
Don't drink anything with calories in it. Do not eat any junk food (french fries are junk food). When you're hungry, eat real food, preferably prepared yourself so that you can track calories and know what's going into your mouth.
Set a caloric limit for yourself. Not something where you're starving. I did 2000 kcal/day, which is pretty reasonable. Then I exercised a bunch over the course of the day; anything I could do at first, which wasn't much (stationary bike and so on), but as the weight came down and my fitness level improved a little I was able to do more and incorporate more variety of exercise. That exercise will increase your caloric expenditure and speed along your weight loss progress without you having to drop down to more like 1500 calories/day which can be unpleasant.
In summary:
-stay high in protein and fiber, and low in sugar. Super low carb is an option but don't feel that you have to.
-Track exactly what's going into your mouth and set a caloric limit that is livable for you but low enough that you'll make good progress.
-Exercise daily in any way you're able. Low impact (elliptical, biking, swimming) cardio is best if you're morbidly obese, since your joints won't hold up to high impact. One hour per day at a minimum will speed you along, and low impact cardio can be done just about as much as you have willpower for. Keep your heart rate up.
-Also do weightlifting 2-3x per week to preserve your muscle mass as you drop in weight.
See Fitness-GAF for more information on weightlifting.
