Your brother might feel distant while on his meds , sure . There is no cure for this disease. It took me years to gain the trust of my family again.
Your brother may also be feeling a little "shell-shocked" about the whole affair. Keep in mind, the world he left when he was ill and the one he's in today are very different.
This "distant" feeling or lack of connectedness is quite common and is nothing to worry about. Your brother would probably benefit from an adult psychiatric daycare program . There are many of them and I've been to them and found them very helpful. You should contact your mental health professional about these programs .
Sincerely,
Don Fraser