After comparing the ages of Avram's children, I believe that Avram had to have been born circa 1818. This would either make him Movsha Leyba's sibling or cousin. Since the census only mentions David Elohiem as a brother I am inclined to think that Avram's father Movsho was Movsho Leyba's uncle. This would make him Aron Hirz Lipkes' brother thus making Avram the cousin of Movsho Leyba.
What do you think? I am open to opinions.