Absolutely get her a "baby" of her own, who she can name, put to bed, feed, burp, change, dress, etc. You can take him/her with you for walks, and you can give her lots of praise for playing gently and lovingly with her baby, taking good care of her, etc.

And you can encourage her presenting her baby to DS for kisses, cuddles, etc too - so she and DS are sort of working together to take care of her baby.

Do you think that would help?