Answer: The simple option is often the best, just tell him he’s going to be a big brother. Kids generally accept this information very well, and will pick up on the general excitement (or otherwise) around a new baby coming. Be positive and upbeat, he’ll have some time to get used to the idea. It can all seem a bit unreal for the first few months until it is obvious that the mother is pregnant and the older child can feel the baby kicking and see ultrasounds of it etc. It sometimes helps to take the toddler for an antenatal check with the mother, look at baby pictures and photos of when they were small and generally involve them in as much of the process of preparing for the new baby as possible. Kids can surprise us with their reactions. When we expect them to behave in a certain way and they don’t it can be such a relief.
There are all sorts of benefits to being an older sibling and although it will also mean he needs to share his parents and grandparents, in the big scheme of things giving him a sibling is a great gift. Your concern for him stems from a place of genuine love, you want to protect his feelings and let him know he is still loved and number 1. Your affection and attention towards him will let him know this everyday.
Cheers
Jane