@unclebob83 Your description of this situation indicates to me that it is very sticky. Does your brother-in-law have any other health problems? Prior to the hip fracture was he active and his mood seemed OK to you? I'm asking this because I'm wondering if there are any other medical or health-related reasons for what you are now observing.

@johnbishop provided some very helpful links to resources. Most importantly in my view is how to approach this conversation and how to accept their responses. While you have their best interests in mind very often people become defensive and will offer a myriad of reasons why they have chosen the path that you observe. I have been through this very process with my mother and father, both now of blessed memory, and it was so, so difficult for me to accept their choices. At some point, finally, I accepted that I did everything I could but ultimately what happened was their choice.

Starting slowly with your brother-in-law with short walks, if he is able, sounds good. He is likely very debilitated from this time in the wheelchair so it may be that at first you don't encourage him for walks but rather standing up from his wheelchair with the use of a walker. He will likely appreciate your visits if these come without strong expectations.

I'll ask the same question as @johnbishop. When do you plan to visit?