I was watching a youtuber react to this movie and at the end he said he was glad they got to Blanche in time. In my view she has died. What say you is Blanche alive or dead?

Mom and I have watched Whatever Happened To Baby Jane? and I believe at the end Blanche finds Baby Jane and it is Baby Jane who dies and Blanche tried to revive Baby Jane but couldn't because before she died Baby Jane tries to call Blanche for help because Baby Jane feels ill and begs Blanche to call for her doctor

Well, in the book, she definitely survives although not much is given about her condition so she could have died later. In the movie I think it's also left unknown for sure. She's found but does she live or die eventually? It's not known.