I agree with getting him in some feed. A higher protein textured calf developer is what I used when raising bottle calves. After he takes the bottle, if you are able to hold his attention and hold him for that matter put some feed directly in his mouth a few times after giving him a bottle. Then leave some in a pan for free choice. He should get into it pretty quick.
You can wean them at around 8 weeks, but I've found they do better if they get milk a little bit longer. If he gets into to feed pretty good, then maybe drop him down to once a day bottle in a few weeks, if all goes well he could be weaned by 3 months. I'd keep him in a calf developer feed for a while though and gradually switch it over to your normal feed. They can go straight in to whatever feed but generally they need the higher protein to not pot gut and they just do better on a higher protein feed.