So the time is coming for me to wean DS soon. I...

So the time is coming for me to wean DS soon. I am not planning to tandem feed and was hoping to feed him until 15 months at the latest. The last week or two though feeding him has become painful. Everything looks alright but everytime he latches its sore and hurts for the first couple of minutes. We are down to one bf a day and that is after his bath before he goes to bed. At breakfast he is on cows milk. So this being the last feed to wean off im just a bit unsure how to go about it. I was also thinking about maybe moving to formula for the bed time feed but have no idea about what I should use. Should I give it to him in his cup or a bottle? I have never used bottles before so I dont know anything about them. And with all the Fontera thing with the harmful bacteria found in some formula's DH doesnt want to give formula to DS at all. So would just giving him cows milk be alright for his age or should I go to formula for a while?