Can’t walk and chew bubble gum?
I think he will be dead in a year, because his most recent pics looks like he something in advanced stages.
He is apparently working on a movie and he is playing a terminally ill professor. I do not doubt he is losing weight to look the part. Most likely in a safe way.
It is possible the weight loss is a result of his role in Richard Says Goodbye, where Depp plays the titular character who decides to live life to the fullest after doctors diagnose him with a terminal illness.