Although I do believe that anything is possible, I also know that the chances are that weaning him and getting him on cows milk could do a couple things.... one, make him wake more as its not nearly as easily digestible as breastmilk and if he has a reaction to it can cause gas , crankiness and stomach pain...

If he is waking because he is hungry, then he will still wake for cows milk. many people think that replacing the breast with cows milk will work because they think that the breastfeeding is keeping him up at night. but its not... its the nursing that helps him get back to sleep .

My idea to WHY he is waking... well... I think that maybe is accustomed to waking and going through the routine like it has been...  so you can try a few different things... start a bed routine with him and watch for his cues... he may be ready for bed before you realize it... so start a half hour before... give a warm bath, cuddle and quiet time, dress and nursing for bed. Nurse him in the dark with nothing but maybe you humming while he nurses to sleep. Wait to put him down until you can take his hand pick it up and drop it and it fall completely relaxed. then you know hes really asleep. If he will take a pacifier, put that in his mouth after he is finished his nursing mostly, so that he still has something to suck on while he is half awake half asleep... let him rest in your arms and settle again before trying to put him down. Lay him on his side and place a rolled up blanket behind him so he still feels as though there is pressure form someone being there.

Its important... no sound, no eye contact, no lights nothing... training him its bed time is important...  when he wakes again a couple hours later you have a couple options, express your milk ( the evening before ) and give it to him in a bottle, or nurse him but for a shorter time and do the process all over again... he may balk some , then each couple nights, reduce the amount of time he gets at the breast. He is looking for reassurance that you are there. NOT because he is hungry.( from what I know about the situation) start with the feeding that is the shortest and easiest to get him back to sleep with.  and then wean him from it that way.... He may fuss some , but just love him through it ... if you get it early enough before he is totally awake, nurse him and he will go back to sleep quicker. unless he is dirty, don't change his diaper in the middle of the night. ( sounds horrible I know but the breathe dry diapers are ok overnight... if he slept all night long you wouldn't wake him to change his diaper so going every 4-6 hour is ok... )  

There is a book called by Dr sears called nighttime parenting that would be great for you to have. and he also has one that is called parenting the high needs child... you might look into that one too :) My son was just like yours... its a long road sometimes... they are very sweet sensitive souls... its a fine balance between helping them be independent but also keeping the same sensitivity and gentleness that you will see come through in the years to come....