How can you get your older female cat to accept a stray and her kittens?

To help your older female cat accept a stray and her kittens, introduce them gradually and carefully. Start by allowing her to observe the newcomers from a distance, using a separate space for the stray and her kittens initially. Gradually allow them to interact under supervision, rewarding your older cat with treats and praise for calm behavior. Patience is key, so give her time to adjust and establish her comfort with the new additions.