21 month old with cp not eating:( please help! :'(

Hi my son was diagnosed with cerebral palsy stage 2 a couple of days ago and a week ago he starts fully refusing his food, he'll only eat Crisps/sweets and that's it. I'm very scared that he's not getting the nutrients he needs especially now with this diagnosis where he needs more nutrients then the avg. Wondering what to do next especially with Xmas coming up don't think I'll be ae to see a dietician before then. Is it worth calling doctors tomorrow? Other then the sweets and Crisps I keep offering healthy finger foods, veg and fruit etc. It takes me roughly around 20-30 minutes for him to eat one segment of orange or one tiny bite of apple. I'm being very patient with him but it takes a long time spending 2 plus hours just for him to eat half of a small orange:( as he gets very frustrated and aggressive aswell. Could there be any other reasons as to why he dosent want to eat? The relation with cp is it being hard to swallow foods, and drink. Which I think he has to an extent as he used to sometimes choke when eating and drinking but has now stopped mostly and does it when he drinks not eats. Any advice is appreciated please as I'm very worried