Is dairy and bread a good way to lose weight?

OK hear me out LOL and I apologize for the long post but I want to give as much detail as possible.

My sister is 38 years old. Has 11 year old son . She does not go to the gym but she does take A lot of steps per day. Looking at her watch it’s about 15,000 on average.

She is the smallest in our I guess genetically quite large sized Italian family. She’s 5 feet tall. Says she’s 110 pounds but I don’t even think she’s 90.

Since childhood she never eats breakfast or lunch. Drove our mother crazy LOL as an adult now nothing has changed 😂

Now as it was since childhood come around 4 PM my sister is absolutely starving! Will snack consistently until dinner time at 6 PM.

But it’s all fatty food.

Things she has daily is 2 cups of milk. One cup of heavy cream. And usually one cup of full fat kefir.
Then will proceed to have things like walnuts. Or almonds. Some sort of nuts. I’ve even seen her eat peanut butter out of the jar 😂

Then typically after that she’ll take a break until about 5 PM. And then will usually have bread or crackers and has heavy fat cheeses. And I mean not just a serving. A lot of cheese.

For example today I weighed it out she had 140 g of aged Parmesan cheese. The hard brick one. Not the artificial.

And Ate that with about a cup of walnuts.
After the milk and the cream and the kefir. 😂

Then typically after that she likes to make toast and dip it in olive oil and spread avocado on it

That’s a typical day. But of course she eats everything. This is just on average.

Now come 6 PM. Dinner time. Today we will be at our parents house for dinner. They are making lasagna.

She will sit at the table. Maybe have six small bites which will take her half an hour to eat. And then say she’s full. Family Eye rolls ensue 😂
But then come around 8 PM she’s usually a bit more hungry. Then yes she will usually finish her dinner. Or she will eat something junk food like pizza or McDonald’s or something.

And then the day starts again. Will only start eating anywhere from 4 PM-ish

I will mention she does drink a ton of water. All day. Even in the middle of the night. A case of 24 last for a few days so I would say anywhere from 3 to 4 L a day. And then will usually have a 1 L bottle of mineral water on top of that.
It’s usually anywhere from room temperature to ice cold. If that matters. I know people have a debate about that.

She doesn’t track calories but I had her yesterday track to see what she eats on a daily basis. Here’s link. https://imgur.com/a/ACUZPiT

For her tiny little size she’s packing in a ton of fat. I don’t know how someone is able to stay thin on 2100 cal a day 🙄 what do you guys think? think it would work for me for weight loss? Thanks all!!