Habits are hard to break...but they can be broken with patience and consistency. Babies should not be put to bed with a bottle. Period. At 13 months, your baby should be sleeping through the night and not waking up for a bottle so you must instill a new bed time routine and hopefully, he will adjust sooner than later.
The first thing to do, you should not give him milk before bedtime. Milk causes cavities because of the sugar and that is something you want to avoid. So, give him water. In a sippy cup. He should not be drinking from a bottle past 12 months. If he protests, then let him protest but stand your ground. To make this bottle to sippy cup transition easier, begin introducing a sippy cup during the day. Put water in it...NOT MILK. ONLY water. Make it fun, like a special treat. Offer the sippy cup at lunch time or snack time or after dinner time. Heck, offer it all the time. He has to get used to drinking from it eventually. When bedtime comes along and he asks for a bottle, tell him bottles went bye -bye (make sure to hide them so he can't see them) and offer him water in the sippy cup. If he refuses, let him refuse but put the cup where he can reach for it easily. If he's thirsty enough, he'll know where to find it. The first few nights may not go well. I understand you are working full time and this must be difficult but you must stand your ground. You need your sleep too! If he gets up crying, go to him, rub his back, belly, whatever works but tell him to go back to sleep. He may cry. You may have to let him cry for his bottle. I wouldn't offer him anything during the night...unless he's sick. Just a back rub and that's it. He needs to understand that night night is for sleeping...not waking mommy up for a bottle.
You have to be consistent. And you need to let your little one know who is in charge. Good luck and many blessings.