Patch Adams was a real person, which is what made the role particularly challenging. That being said, it was a role that was almost custom made for Robin Williams. It called for a dignified combination of humor and the seriousness of disease, and Williams delivered one of the best performances of his career.
Personally no I do not believe that "Patch Adams" was one of Robin Williams's best roles that he has starred in. I have never seen him in this role. I have however seen him in Flubber and Ms Doubtfire. I enjoed him in both of these roles I think they were his best.
But how can you choose? He had so many great movies! Flubber, Miss Doubtfire, Jumangi! There are too many to pick from, he had a bunch of great movies. He also did really well in the more serious films he did, he just had a very well-rounded talent. RIP Robin
Robin has had a stellar career by all accounts. He even stated in one interview that after he won the Academy Award, he still had fans refer to him as "Mork". His character on "Mork and Mindy" was the breakout role for him and that will live on for many generations to come. As far as the silver screen is concerned, his character in "Mrs. Doubtfire" is arguably his best work in Hollywood.
That depends on what you mean by "best". Most popular? Highest money maker? Robin Williams was a true master and I don't recall ever seeing him under perform in any role. Sure there were films I didnt think much of (Click comes to mind) but that was the story at fault, not the actor. Personally, my favourite roles of Robins was as mrs Doubtfire.