It's obvious that your dear Dad is trying hard, as best as he knows how to. He needs credit for sticking with it as much as he has.

The danger in LC'ing and then swinging to the side of the low-fat/restrictive calorie pendulum is that he is playing risk with his organs.

Please, please encourage your dad to stay with LC'ing. Maybe he can pinpoint for you what are the hardest struggles for him. Also we have a forum here for people who weigh as much as he. They totally understand what he is going through. Usually our endeavors have more importance when we receive encouragment from people who have truly walked in our shoes.

I wish you the best.
Annie-Pie