Now I am profiting from my Bitcoin investments then and one of my colleagues is now in dear need of financial help, he needs some help, not life-threatening but money, and now I am not ready to loan him any money as long as it affects my overall Bitcoin holdings.
Well its your prerogative to help him or not. I think you can help him with your extra funds or profits if thats fine with you but also you can tell him that you dont have money for the help or aid his asking its quite simple. A friend will understand the need of one, it depends on how your friendship matters actually.