I am not sure what you mean by ‘handle’ being around the others, but as this is a reasonable question, I will attempt to answer to the best of my ability.
For the most part, I prefer to keep to myself. I keep my interactions with the other members to a bare minimum, speaking with them only when strictly necessary (with one exception). In particular to the members you ask about, Demyx avoids me like the plague, and I am perfectly content with this state of affairs. He is perfectly capable of performing any of the duties he’s assigned, but he is lazy and completely unmotivated. He often either outright dodges work, or attempts to manipulate other members into picking up his slack, which I find much more distasteful than if he’d merely been incompetent. I interact with him only to berate him for failing to carry out his duties, and it is always a headache to do so.
As for Xigbar…he is another member I take pains to avoid whenever possible. He has a hidden agenda with everything he says and does. Almost every sentence he speaks has a barb in it somewhere. If you cannot find it, it’s only because he’s hidden it too well, and you can be sure he’ll be laughing about your inability to understand the joke. Of course, he is the Nobody closest to Xemnas, and so as second in command I cannot avoid interacting with him. Still, I try to avoid it whenever I can.
Axel, on the other hand, is the exception I mentioned above. He is my last connection to my human life, and being near him reminds me of being human as much as I am capable of remembering. I do try to be near him whenever possible, but my workload affords me little personal time. Recently, he has also taken to avoiding me in favor of the Keyblades, which makes it a bit more difficult to arrange times to meet with him. Nor does he seem all that pleased to see me. But he gets himself into these sorts of 'moods’ every so often. He’ll get tired of it soon enough.