Agree also with a trainer/behaviorist. I will go further and say private classes, especially with behavioral issues. While your pup is being trained, you will be trained as well. Since this is a family pet, all should participate, so the handling of this pup is consistent - no confusion for him or you/family. The big plus for you, is you will gain confidence in yourself to handle him.
While you are doing the research for the trainer; a few things to keep in mind. You stated you and your family are scared of him and/or scared when handling him around family. Your dog is picking up on that and this can cause him to act out more. As tough as it may be, stay calm when handling him.
When you are out and have him on leash and he acts out. Your first instinct is to pull him back, don't pull backwards. He will automatically pull/lunge forwards even harder. Instead, step to the side and turn, walk him away.
Post where you are located, someone may be able to give a good recommendation for a trainer in your area.