I agree be totally honest with her and tell her everything that is going on. I agree also with Sherie on letting her help choose things for the new baby, include her in any way you can, send her photos of scans and of your belly etc. Don't put her on the outer because you're afraid of what her mother might so/say. I agree with Rayla on counteracting what the mother does with lots of love and patience and also reassuarance that she's not being replaced, just added to IYKWIM? And yeah the baby giving her a gift might be a nice idea when he/she arrives, then she will feel included in the family and not left out seeing as the baby will get a lot of new things.