Joysh -- What a wonderful sister you are. I agree with the suggestion to go with some of the high calorie, healthier foods. Working in a few things like avocados (mmmm... guacamole) and good quality cheese will be delicious for your sister -- and if for some reason you feel your resolve waivering, they won't take you out of ketosis.
I just got back from an unexpected trip to the midwest to take care of my mother, who is in a nursing home for rehab and not doing well. One of the issues is nutrition. She isn't eating much and all she wants to eat is unhealthy -- pepsi and dessert. Trying to get her to eat was such a challenge! She was looking at me with my protein bars and complaining that I wasn't eating. I explained that they are healthy and that in the evenings I was having a big meal. I was disappointed that I hadn't brought some of the more palatable packets with me on the trip -- I would have shared them with her to make sure that she got some protein.
I guess the victory is that, in spite of the unexpected trip and stress, I stayed 90% OP. Just 90 percent because at the end of a particularly stressful day, I ran a bath and fixed a vodka club soda. But today is a new day, I'm home and looking forward to a 100 percent OP week.


I have the same mentality and I'm enjoying changing things up a bit.