Are Friends and Family Really Important When It Comes to a Person Going Through Addiction Treatment?

Will having friends and family’s support really make a difference for the patient? My uncle is going to go through inpatient rehabilitation so that he can get treated for his alcohol addiction. The thing is, his family’s not being supportive. They look at him as a disgrace. I was just wondering if this may have an effect on him and if it would be better if he has their support.