My daughter in-law has BPD traits

[Li]

My daughter-in law has BPD traits. It seems to be prevelent in her family (mom & aunt). She is extremely emotionally abusive to my son. I am concerned because from my research it can also have an effect on children as early as infantcy. My granddaughter is 7mos old, how can I support her at this young age to help counteract any negative effects she may be experiencing? How can I also support my son in this toxic relationship?

[Turkish]

What kinds of behaviors is your GD experiencing that you can tell (other than witnessing her mom verbally abusing her dad,  which I imagine it's a given). How often do you see your grand baby?