Surely, a lot of unsolicited advice will come your way as soon as your belly started showing or as soon as they learned you are pregnant. The best way to deal with is to just smile at them and politely change the topic.
Advice can be found in a variety of places: parents, teachers, friends, family, neighbors, ministers, counselors, even strangers on the internet. Imagine that, one of those strangers' offer is on the discussion page.
Shannon's Deal - 1990 Strangers in the Night 2-4 was released on: USA: 16 April 1991
When a baby cries when it hears a strangers voice but not it's mother is not an illustrates. This just mean that the baby is comfortable about it's mother and knows her voice.
Perfect Strangers - 1986 Hello Baby 2-1 was released on: USA: 17 September 1986
Perfect Strangers - 1986 The Baby Quiz 8-4 was released on: USA: 30 July 1993
No, and he should not be frightening you with such threats, your baby is not a pawn to be used to threaten you or control you. If you really believe he would try and do this, you should seek help and advice on how to deal with this from social services.
Perfect Strangers - 1986 Since I Lost My Baby 2-13 is rated/received certificates of: Australia:G
Perfect Strangers - 1986 Happy Birthday Baby 1-6 was released on: USA: 29 April 1986
Perfect Strangers - 1986 Since I Lost My Baby 2-13 was released on: USA: 14 January 1987
Perfect Strangers - 1986 The Baby Shower 8-1 was released on: USA: 9 July 1993
Perfect Strangers - 1986 Yes Sir That's My Baby 7-16 was released on: USA: 8 February 1992
Ask a doctor not the internet. You really trust your baby's wellbeing to strangers?