A.H.
It will be very hard to get rid of it wile your younger child is still on it. I would suggest at about 8 or 9 months replace all the bottles with the sippy cups that have the soft silicone tops that will be ok for both your babies. My son was off the bottle at 9 months this way. But don’t stress the bottle thing haw many people do you know who have issues because they were still using a bottle at 2. In the mean time if you are worried about his teeth they also sell a bottle that has a transition nipple that is more like a sippy cup but still looks like a bottle.