How could a person with very limited mobility somehow create brain endorphins for a sense of well-being?

Being creative helps. Physical exercise isn't the only thing that can create endorphins. Within the mobility limits surely there is something one can do to be creative. It has to be something the person likes and can actually do. Trying something that is unrealistic because it sounds good but is beyond the persons ability or interests to do is going backwards. Choose carefully and it can help.
Complication of Tics. Shame, embarrassing and social ostracism. Fequrnt motor tics. May lead to articular damage , and frequent sensory tics may lead to sufficient scratching to cause excoriation.