I have just answered a very similar question with an almost identical thesis statement, and so I must warn you too to be very careful of plagiarism. Your thesis statement as it stands looks as if it has been lifted from a website or textbook. You need to make very sure that everything you write is your own work and is not "borrowed" from other sources. If it is, you need to indicate that by putting the quote in quotation marks and indicating the source.
However, generally, by far the most interesting aspect of the life of Robert Louis Stevenson is how he ended his life. He moved to Upolu, one of the Samoan Islands, and bought some land and established his household there, before dying there after trying to return to Scotland twice but failing. We can perhaps interpret this as part of his own desire to live out some of the adventure that he created in his stories.
If you are writing an essay on his life, you might wish to include this, perhaps basing your essay on the following thesis statement:
Robert Louis Stevenson's life was an attempt to live out the adventure that he had created in his stories.
However, I would ask you to think very carefully about what precisely it is you want to communicate in your essay. Is it going to be focussed on his life or his work? What is the main point you want to state? The answers to these questions will help determine your thesis statement. Good luck!