IMHO, I think it will be wonderful for you son. He will not only br able to be around you more but he will have the chance to really bond with the new baby by helping with his or her care, rather than "maybe" seeing the baby for a few minutes a day during these critical first years.
I'm a new homeschooler but saw a difference in our three the very first week and they are older, 14, 11, 11. Good luck.