I never got to share this with anyone, but I thought I should here in case it helps anyone.
My biggest regret was being in denial about it being time for my boy. He had gotten sick before and recovered, so I kept thinking he would recover again, but by the time it was clear that he wouldn't, it was too late. We were planning on taking a couple of days off work to focus on him and do all of his favorite things, but we were one day too late.
Hope no one else makes that mistake.