No person other than a voter preparing his ballot is allowed within the guard rail, except as provided in this section. A voter who requires assistance to vote by reason of blindness, disability, or inability to read or write shall make the fact known to the managers. The chairman of the managers shall appoint one of the managers and any person of the voter's choice, other than the voter's employer or agent of that employer or officer or agent of the voter's union to assist the voter in preparing his ballot. After the voter's ballot has been prepared, the person chosen by the voter to assist him shall immediately leave the vicinity of the guard rail. In lieu of the above assistance a person may have a member of his family or, in the case of a blind voter, any person of his choosing render him assistance in voting without the presence of a manager. The term "family" means spouse, father, mother, son, daughter, brother, sister, grandfather, grandmother, grandson, granddaughter, aunt, uncle, niece, or nephew.