Jealousy among dogs is very real. It is not a good idea to be a multi-pet owner and have favorites.
Playing favorites has a lot of negative impact on dogs. Although dogs react differently, they could become aggressive, withdrawn and depressed, among others.
But I admire dad for not giving in to a jealous dog. He continues to switch his attention back and forth and kept the jealous dog in check.
Do not let your dog bully you into giving him/her all your attention. Teach them to share the love <3