I found when you cut out the milk they start to replace it with water really quickly, and then they eat more food in just a couple of days.
Is he ok weight wise?
We were having problems with our 16m/o not putting on any weight (for 5 months or so)! So a paediatrician and dietician managed her eating plan and we put her into a firm routine which works really well. She is putting on lots of weight because we cut it back to:
7am: wake, breakfast (porridge with milk and a teeny bit of butter or weetbix)
7.30am: 120ml formula
9.30am: small fruit snack & water
11.00: lunch (we had to go back to puree food and add avocado, melted cheese, healthy oils and ground nuts, just to make sure she was getting enough calories)
12.00 - 2.30pm: nap
2.30pm: small drink of milk or home made juice (okayed by our dietician, but I know hps of people disagree with giving their kids juice) + cheese or small amt of yoghurt
(Drinks of water offered throughout the day, but not 40 minutes before meals)
5.00pm: Dinner (puree, with stuff added, then finger foods like pasta)
7.00pm: 120ml milk and bed.
No feeds over night. I think you could pretty safely cut out the overnight feeds, if you feel comfortable with that?
It could be a couple of nights' protest but it'll be worth it if you have decided he should be eating more and drinking less (that's what we decided but we just had to be firm with ourselves for the first couple of nights).
Our DD has done so much better since being on a routine. I am also less stressed! There was nothing worse than preparing meal after meal that she would just refuse or pick at. She was otherwise totally happy, but when your kid doesn't eat it can really max you out! I was dreading meal times but after a couple of days of only doing stuff that we fed her, she suddenly went from eating only 600 calories a day to over 1000. It is much easier to be able to give her three meals a day, with a couple of snacks and only a couple of milk feeds, rather than having her having milk all through the day and night.
We were told they should be getting about 900-1200+ calories per day and that after the first year, this didn't need to come from milk. Check with your doctor though! They can be pretty helpful, I certainly learnt a lot.
Good luck, and don't worry, he will get the hang of it and not starve if you have decided it's time for him to get his nutrients from food! I was worried about this too, but have found this so much easier.