Perhaps think how he usually communicates with you? I am guessing that the family WhatsApp group is the way each of you chat, so instinctively at a time of worry he would have wanted to let everyone know and get back to his partner and new baby as quickly as possible. I agree a phone call would have been magical, but I am guessing he isn't in the habit of picking up the phone and calling, only one of my four children would do that unless I was wanted very urgently.
Do send a text tomorrow asking how the three of them are, sending love and congratulations and if a home cooked meal would help once they are home. keep it brief, and I hope you will get an early reply! 
Have you ever been to see a Spiritualist



