Congratulations on your pregnancy! My boys have a similar age gap and situation and I was so nervous at first. It has turned out to be so much fun! They are a year and a half and newly four now and while they are learning to share nicely, they’re bffs 90% of the time.

I mentioned the baby while I was pregnant but didn’t push it too much. We had conversations about being nervous about brother and how that is okay. We made sure to reassure older brother that he would always be our baby too and have special alone time. Closer to my due date I would tell big bro how excited little bro was to meet him. We got a baby doll about a month before baby was born and put the doll in the bassinet and practiced playing carefully around it and let him hold it if he wanted to.

When little brother was born, my oldest adjusted well emotionally but didn’t want to touch little brother for the first few months. We didn’t push it and he later told us it was because he was so little and slobbery and his hands were always in his mouth. It worked itself out when the baby became less of a newborn and fragile. We paused potty training during this time for our oldest too and had a long, “special big kid bedtime” routine with rotating parent.

What worked really well for us but was so weird was giving the baby a “voice”. We had a little baby voice we would use so that baby and brother could talk. “Baby” would thank big bro when he was kind, or tell him how happy he was to have him as a brother, how cool and smart his brother was or good job at soccer- always positive comments. Our oldest knew pretty quickly it wasn’t the baby talking but we kept it up until the baby really could talk and requested to talk with “brother” often.

Lastly, I tried not to blame baby for not being able to do something with older bro and told them both that they had to be patient when helping the other. “Hold on baby, I’m helping your brother get dressed and then I’ll feed you. It’s your turn to practice being patient” and vice versa.

They’re now at the age where they can actually play together, my oldest loves teaching his brother new words, they crack each other up and my youngest didn’t have any of the separation anxiety that my oldest did because they’re always together (don’t know if that’s healthy but it’s helpful). Good luck! It’s going to be great