Without a doubt. If you have an addiction to a substance and have a family everybody is affected in some way. Sometimes subtle sometimes dramatically. Addiction is a disease of the entire family and good recovery usually requires everybody to get help. It's why al-anon exists.
Yes absolutely. The answer is yes definitely. You need to get treatment to stop your addiction- whatever addiction that you may have.
Yes it can. The overwhelming majority of families in which a member has alcohol or drug addiction are profoundly affected by that addiction. There are many treatment programs that include family assessment and therapy, as well as self-help groups similar to alcoholics anonymous (alanon and nar-anon). First and foremost, you need help, but the rest of your family can benefit from counseling.