You have a dew options, each with their own pros and cons.
1) Keep his routine the same as it's always been, with the exception of the bottle. Put up with his nightly tantrums, and likely middle of the night wake-up crying, for AT MOST 2 weeks. At the end of that time, you ALL will rest soundly again. Pro- no more bottles, better for teeth, only 2 weeks. Con- 2 WEEKS!, hard on everyone in the house, exhusting.
2) Keep his routine the same as it's always been, except put water in the bottle. He may be willing to except this as a comforting tool. If it works then GREAT! My ped says water in bottles is no big deal. He preffers this to pacifires. Pro- He see's the bottle as soothing, water is better for teeth, If it works you all go to sleep easily. Con- Still a bottle, drinking TOO much water in bed may cause him to start leaking, and IF he leaks- even worse time get him back to bed.
3) Give up and hand him back a bottle of milk. Pro- easy to go to bed. Con- Teeth, teaching him to get his way, you feeling like you quit... you can see I don't like this option. Once you start, you need to continue in the same direction. YES, I KNOW it's hard!
In my opinion, the 1st choice is your best choice, followed by number 2. You could try diluting it if you need to.
Hope it helps~ J.