Paediatric doctor advice

My daughter has had some trouble gaining weight but recently gained some weight. I have had success as I managed to reduce breastfeeding and as a result her appetite had increased. She still wakes at night to feed and I have tried my hardest to stop this but not had any luck yet. I am not willing to sleep train as I don't agree with it. However the doctor had told me to start putting nesquik into whole milk in a cup for her for sweetness becayse breastmilk is sweet. I am so shocked. There is 16 grams of sugar in one serving even a quarter of that is 4 grams of sugar! NHS dietary advice is so outdated and quite frankly shocking!!!