On reading your post, I googled this very sad news.
It is unbelievable, but yes, apparently died by asphyxia. Very upsetting, he was a wonderful man, very funny. My memories are of Aladdin and Mrs. Doubtfire, films my children have grown up with. And of course, Mork and Mindy when I was a kid. Nanu Nanu. I have adored him ever since.
He suffered from depression, alcoholism and drugs in his lifetime but he had a golden heart, even with the pig valve. He had the heart operation I am to have so he was my "go to" that he had survived and gone onto have a good life. I don't usually cry over Hollywood stars but Mr. Williams was in no way of the "normal" catagory, thank goodness.
R. I. P. Robin, goodnight, God bless. Xxx