what are the best ways to warm your three year old up to a newborn .? he's three on Sunday his…

what are the best ways to warm your three year old up to a newborn .? he's three on Sunday his brother is scheduled to be born may 31st & now that it's getting closer he gets mad &cries; & says he don't want a brother when i bring it up i try to get him excited about it ik he just loves to be the baby though ugh .