I can only comment on what I've read about Xenical and that is the reality that it can nudge weight a bit but it is not a "significant" weight loss stimulator.  It will help your wife to absorb less fat - but that's about it.  In addition to counting calories - and I would not go so low as 1200/1300 right now since it leaves little room for modification if you hit a plateau later down the road.  So I'd shoot for about 1500 calories/daily plus 45 minutes to an hour of exercising daily which can be just aerobic (pulse raising -burn calorie exercise) or a combo of weight training/aerobic.  I'd also make sure your wife is eating at least a "high fiber diet" meaning lots of fruits, veggies and whole grain carbohydrates (cereal,sweet potatoes, bulgur, breads, etc. that have atleast 6 grams of fiber per serving).  Fat free dairy and a variety of proteins (beans, fish, white meat/skinless chicken, soy foods). Cehck out the resources on this connection and I;ve just published a book Fat Families Thin Families available on amazon.com.  It would actually help your family team up so your wife succeeds with her goals while you all benefit with better health habits.