She's cooking for someone with lactose intolerance ( even if there is such a thing as being 'partially' so ), but I see a great deal of dairy being put on his plate.
Partial lactose intolerance is indeed a real thing.
All babies are born with lactase, the enzyme that breaks down the sugar (lactose) in m!lk. This is because humans, as mammals, are meant to nurse their young with breast m!lk. Throughout most of human history, dairy wasn't part of our diets beyond infanthood. Their was no evolutionary need to sustain the ability to break down and absorb m!lk sugar. As we age, the amount of lactase in our small intestines begins to wane. This tends to happen gradually, so most people don't realize they've become lactose intolerant overnight. It's called
primary lactose intolerance. (Though we all become lactose intolerant if we live long enough, the condition tends to strike young in those with Mediterranean roots, like Phil.)
The other scenario that might pertain to Phil is called
secondary lactose intolerance. What this means is that illness, infection, or injury has temporarily wiped out the body's store of lactose. One example would be having abdominal surgery, and needing to take antibiotics after the surgery. An individual in that situation couldn't go back to eating dairy right away. They have to build up their tolerance, starting with easily digestible foods with little lactose, like yogurt.
So, either through aging or illness, Phil has lost the ability to handle foods with a lot of lactose. He likely couldn't handle drinking a tall glass of m!lk or eating a big bowl of ice cream without taking Lactaid. But in moderation, he'd probably be fine having some Parmesan grated over his penne.
