A few ideas
I have been doing RFL for 2 months (and have before in the past) at 90g of protien when I should be at 130g according to the book. I haven't noticed anything. I could probably eat the other 40g, but I've been lazy about it (I could easily eat a 1kg steak, however, so this is not a stomach stretch issue more that I am actually lazy about eating right now.)
In regards to your wife, it sounds like she's doing well and a little worried. If she does notice some kind of issue (no idea what) then she'll have to up the intake. In that case, people have been known to be creative with protein powders and egg whites. There's also that vegetarian meat stuff that is lowish calorie and moderate protein. You can probably find all you need online to achieve some kind of varied food intake (if she finds it to be an issue).
Another thing might be eating more frequently and smaller quantities with longer gaps between meals. Reducing vegetables might create more room for meat if that's an issue (perhaps taking a fiber supplement?) Also, making some kind of 'snack' food like grilled chicken sticks with some good quality spices might be a godsend. She can graze and get her protein intake down. Finally, bear in mind that very lean cuts of meats are frequently not that far apart in calories. Yes, very lean red meat has more calories than fish or chicken, but it's usually not a massive difference (becareful of pork, however). A daily platter in the fridge of ham, cooked fish and little chunks of steak with low calorie dipping sauce might help. Few of us can enjoy that luxury, but it might achieve what you are looking for.