thank you so much. at first, i was going to create a family of 3, mom grandmom and myself. then kill the mom and have myself and grandmother left. but not sure if this will even work. i really don't know how to use mods. never have and i am not tech savvy. lol but thank you for the suggestion.
What you described should work, although you will probably need some extra steps. Here's how I'd attempt it:
Create the sims in CAS. You will have to make the grandparent an elder, the parent an adult or YA, and the child no older than teen. Then set their relationships accordingly. Unfortunately, you can't set adults as parents of YAs in CAS, I'm pretty sure.
Play this family in a throwaway save. Start the game and turn on testing cheats. Shift-click on the teen to trigger age transition and make them YA (assuming this is where you want to start.) Shift-click on the parent sim to trigger age transition until they're elder, and then do it again at elder. This should kill the sim of old age and generate a tombstone you can put in one of the sims' inventories. Or if you wanted them to remain adult or YA, you could just pick another death like starvation, by dragging the hunger bar to zero and waiting it out, or having them work out until fatigued and go swimming, and let drowning do them in. Or set a fire, etc. Re-dress the YA grandchild how you want at the dresser/mirror (or edit in CAS cheat), and if the age-up didn't give you the traits you want, use testing cheats to change the traits.
Once the family dynamic is correct, make sure the dead parent's tombstone is in either the grandparent or child family inventory. Go into edit town and save the household to the bin.
Now you should be able to place your family from the bin when you start a new game.
