@WoodenTrain
My DD16 is the same height as your DS.
I would take him to A&E.
DD was 44 kg when I took her to A&E in November 23, I was told she was at medium risk of death. They sent her home and CAMHS got involved.
Her weight dropped to 41kg, at this point she was fainting, freezing cold and we thought we were going to lose her. She was on complete bed rest for two months at home. My heating was on constantly as her temperature was 35. I had the ambulance out twice, she fell down the stairs and was unconscious, it’s been the scariest three months of our lives.
I asked the ED clinic to admit her to inpatient just before Xmas as she was refusing food and she was given a place at a day patient unit as an alternative to being sectioned, where she is now stable, vitals are done every day with weekly blood tests, medication and she is gaining weight each week. If they have any concerns at the day unit they would admit her immediately to in patient. I wouldn’t hesitate to take her to A&E if she was refusing food and fluids. She cannot afford to skip a single calorie. She has a psychiatrist, dietitian and nurse working with her and she attends the school sessions at the day unit.
They go downhill very quickly once the weight is so low. Once all the fat has been eaten up internally it attacks the vital organs to try and survive. DD has heart and liver damage and is fully aware of her health issues. Waiting for her bone density scan which will no doubt give her an osteoporosis diagnosis to add to the list.
Current wfh is 72…..it was was 68.
I wouldn’t bother with the GP, A&E is your fastest route to proper help.