Terrible news. I was very fortunate to meet him last year at Comicpalooza in Texas for the 30th Anniversary of Aliens. Looking back, he was vibrant and sharp, not so different than the roles he played. Watching him reunite with Michael Biehn and watching them embrace, share stories and play catch up while I waited for an autograph (as they're booths were adjacent) was one of the coolest actors-in-real-life moments I have ever experienced.
May this be a solemn reminder to not shrug off time with loved ones or taked the things we have for granted. We never know when our time here is up, so make the most of it. Find your higher calling, never say never, and live like your loved.