My DD is using a sippy but will only have water. If I put formula in it, she gags and throws it. So for now she just gets water in it.
And actually a sippy is really not a big deal. Even if your LO skips it all together you may just have less problems getting him weaned from it later on;). I'm already giving DD some water also out of a regular cup, too. As in straight from the cup. A lot of things are sold for babies and some of them are very common and standard but it doesn't mean that all babies need to use them or that they are behind in any shape or form. Your boy is doing just fine :)
Oh and my DD doesn't hold her bottle. She actually can (and so does your DS I'm sure) but she just doesn't want to. She likes to be cuddled up on me, play with my hand and drink her formula. No harm in that :)