Yeah, sounds more like a TIA (transient isthemic attack) than full blown stroke.  I had one about 20 years ago.  First time I knew I couldn't drive.  Right arm numb, leg kinda dragging, slurred speech, blurred vision.  
Had the wife drive me to emergency room.  By time I got there, it was over.  
Been on one aspirin a day ever since.  No recurrences.  Much later I attributed it to using a vibrator around the back of  my head and neck to relieve a stiff neck.  Duh, not a good idea.  Think I jarred a clot loose.  Just my guess.
Sure got my attention though.  Led me to try to relax more and smell the roses.  Like many people, I had my share of stress.  The TIA eventually became a wakeup call that I think has helped me to a better life.  Hope your father-in-law recovers fully.