What advice would you give to a friend who struggles to let go of physical and emotional things and experience ?

I guess my first question would be, why would I want them to let go of them? If it is hurting them or holding them back, I guess that would be a good reason. I will then identify why they struggle to let go. Could it be dependency or safety blanket, how deep rooted is the problem? Depending on how I analyze it, I will try to help them. I can give them different perspectives, or talk and listen to them, or assure them that they are not alone. But if I think it is beyond my power, like a PTSD, then will ask them to seek professional help. It won't do both of us any good to try and fix something ourselves when a pro is necessary.