many people who want basic health and fitness will be overwhelmed with crossfit concepts unless they are scaled in a huge way!
seriously, if they are overweight and coming from a sedentary lifestyle, i would start them walking 4 times a week with a few body weight exercises at the end (squats, modified push-ups, some sort of rowing exercise). once they can walk 30 minutes and feel good about walking briskly, you can add other days in there. just dont do the strength work daily. oder people who express interest in basic lifestyle changes are not likely going to warm up to a gung ho program like crossfit. if they get walking and that is getting them off the couch then that is a huge step. you dont want to frighten them into thinking they may as well not even try since it is so far from where they are now.
think of it like a college degree...it may take years before they feel the level of committment you and i do on fitness.