Family members cannot typically treat a loved one's eating disorder because

Family members cannot typically treat a loved one's eating disorder because they do not have enough knowledge or resources

Explanation:

An eating disorder is an illness that affects the way we think about weight food and exercise. Eating disorders are one of the most dangerous mental health issues, since it can severely damage the body.  Family members cannot treat the disorder since they lack the knowledge and resources. The best way to treat this illness is to visit the doctor.