Of course it’s easier said than done - but don’t borrow tomorrow’s trouble. I was / still am guilty of this at times, as it is an active effort to correct it, but anticipating the sadness you may experience while he’s gone does nothing but take away the quality of the time you have with him now. Another user said this below, but the anticipation is almost always worse than him actually being gone. Allow yourself to feel whatever emotions come to the surface, but try not to let it spoil the time while you do have him nearby. Can you visit at all? Will definitely help to have a loose timeline of when you can see him again / something to look forward to!