I did not really have any connection to the 90210 / Riverdale shows he worked on although I did see him on a recent (2017?) Hallmark Movie and he looked very strong ans healthy.
There is little warning when a stroke hits. My sister, myself and my brother in law were enjoying a pleasant Saturday morning out on a patio deck having some breakfast. I had just stepped into the house when I heard my sister scream. I ran out and saw my brother in law had just lost his balance, dropped his arm, and looked spaced out. Thank god, my sister and I called 911 immediately and within 10 minutes, he was at the hospital (thank god a small upstate NY town on a weekend or the reaction time may have been worse). He was moved to several different levels of trauma centers as the severity of the stroke became clear and was only given a 20% chance he would make it through the night with the entire family gathered. Well, he survived thanks to a brilliant surgeon (we were told later).
Well, about 15 months of physical and speech therapy later, he has been able to resume his life and work (speech about 90% and partial paralysis on lower left hand only)
My lesson learned is to not fool around with loss of balance and think it is just dizziness or vertigo. A stroke is so fast. You have to get help immediately. Most concerning, he did not have any of the classic precursors like high blood pressure etc and was in very good shape (unlike me).
Again, RIP Luke and condolences to the family.