SIRES > synonym of ancestor. Your sires sires sire is your great grandfather

ISAAC > a biblical ancestor

ELDER > see great grandfather

WOMAN (/WOMEN) > women are great

DADDY (/MOMMY /MUMMY /MOMMA etc) > your ultimate ( great here meaning chief or principal) ancestor

UNCLE > where “great grandfather” means “distance” an uncle can also be of a greater distance than a father.

BEARS > where great is large, also a pun on “bearing children”