Babies with older siblings

Mine was 5.5 years when baby came along, and it didnt help that they have different dads, and his dad isnt really that interested in him...

I didnt really push it when Jae was little, I waited until she was old enough to interact (about 3-4 months with smiles, noises, and could play with some toys etc) then asked him to 'help' me with her by sitting with her while I had to do something in another room (so he didnt feel like I was hovering) or setting them up on the couch so he could give her a bottle, getting him to choose a toy for her out of her toybox... I just took it a little bit at a time, and now that she is older and 'doing' more, he seems to be enjoying that time together more than at the beginning...

12 years is bound to be harder as he has the whole 'pre-teen angst' thing going on... all I can say is dont push it too much or he will go in the opposite direction... Once baby is a little older, you coud try getting Mr12 to help out so he feels like he is just as important in the family as everyone else (not so much with nappy changing, baby sitting etc, there is a 16 year age gap between my brother and I, and the last thing I wanted to be doing was changing nappies... how ironic that almost 4 years later I had my own to change nappies for!)

Is he into anything like photography, or art or something that can be used to encourage him to interact with baby? If you have a decent digital camera, maybe get his help to set up a little DIY family photoshoot? It could be his 'project' and involves the baby, but not so much that it would make him feel 'forced' to interact if that makes sense?

My older daughter was 11 when I had DD2 so we had a pretty similar age gap... At first babies are pretty boring really and after the initial excitement of getting a baby sis wore off DD1 seemed to lose interest for awhile... However, when DD2 was older and could interact more she became much more involved with her. It is a hard age gap though, as sometimes she just doesn't want her 2 year old sis hanging round her and her friends but DD2 just adores her....
I didn't really have to do anything to encourage their relationship, it just happened as DD2 got older and more interesting... The thing I found the hardest (and still do) is how time consuming little ones are and I worry that DD1 doesn't get enough time/attention... as I guess that could lead to resentment

DD was almost 12 when I had DS and she was very strongly opposed to having a sibling. They were firmly bonded within a few months of him being born. Once the baby starts to do things especially recognise and smile at his big brother it will come quicker. In the meantime I wouldn't push the issue. His friends enthusiasm will rub off.

I'm 23, DB's are 18, 13, and 6 (I think) respectively. Lol I can't figure out the math, as to who was what when they were all born. What you are saying sounds familiar though. He's a 12yr old boy, babies, siblings or not, won't rate to high on the priority list

I think as the babies get more interactive, the kids get more involved, and I agree with what they what has been said about friends enthusiasm rubbing off :D The littlies become a chick magnet for much older brothers later on too It'll take a bit of time, but it'll happen