It doesn't matter if you have other children, when a new baby comes into a family, many pets are lucky to get any attention at all for the first few weeks and a lot of parrots feel shunned/forgotten and become jealous that they have lost the attention they once held.....
In most cases this could have been avoided, had the bird been prepared for the new arrival by weaning it from the degree of attention it enjoyed before the baby's birth.....I know a couple who have a couple of large birds & they went so far as to buy one of those babies that are really lifelike & included their birds into the preparations & homecoming of the baby.....the birds actually quieted down their calls & screams.....
Maybe he's just decided to get on with his life & administer some of your own medecine (at least as he might perceive it).....a lot of siblings feel some measure of jealousy when newborns arrive, take up all of the parents' time & attention.....even though these parents insist their attention is spread out equally.....not always true.....
