Hi -
So, technically speaking if you do not have a kosher home, then nothing you prepare will be Kosher. For example, that means your kitchen would need to be blessed by a rabbi after it has been cleaned and no other non-kosher foods have been removed from the home. Most kosher people know that homes they are not visiting are kosher. It also works in the corporate world, people who keep Kosher know that they will be going to restaurants and eating at events where the food is not kosher. What most kosher-keeping people do is just eat vegetarian. This will be considered kosher-style. They generally will not go for meat (even if it is kosher meats such as chicken or beef) as it needs to be kosher meat, which is expensive and I do not even know where you would go get any here in the high desert. If you want any vegetarian meals, I can help, just let me know. But in all honesty, I would probably reach out to the person and ask them to help you be prepared for their visit. And like other people said below ... just because they are Israeli does not mean they keep Kosher. There are a lot of secular people in Israel.