No it is a coincidence that they have the same last name.
No he just has a sister as far as i know
Deion Sanders was #21 throughout his NFL career until he unretired to join the Ravens, when he had #37.
Deion signed with the Braves prior to spring training of the 1991 season and was with the Braves through May 29, 1994 when he was traded to the Reds.
No they are not related