Hank Deutschendorf passed away on June 14th, at the age of 28, after losing his battle with schizoaffective disorder. May he rest in peace. Condolences go out to his twin brother Will (and the rest of his family); together, the twins played little Oscar in Ghostbusters II.
I was on the way to Nashville when this would have been posted, on June 21st. I only found this out because I happened to suddenly have a desire to read through the TV Tropes page for Ghostbusters II earlier this morning. I spotted a link to the first article on his death that I linked to, which was situated on the YMMV page for the film.