I do think they love each other, just as they love their Mommy and Daddy and older brother (and the dog). But it has more been surprised delight when the other infant made an appearance, "Ah, yes, you again! I'm so happy you are here for tummy time!" I've noticed it has been similar to our oldest's first couple years when my husband was underway so often. He didn't quite get that it was Daddy who was gone, but he knew someone was gone... and it threw him off a bit... and he was always happy when Daddy showed up again.
The past couple months, however, have been different. C sleeps much more than O. I take O out of the room when he wakes up and let him come play with his older brother D and sit with me. When C wakes up, O will sprint to the baby gate and try to say his brother's name. It is adorable. If I leave the baby gate open (we have a ranch style home), O will take off down the hallway, even if C is happily sleeping, and sneak into their shared bedroom to check on C. I've found him quietly playing next to C's crib or poking his hands in between the rails while saying his brother's name. I feel like he wonders what his brother is doing since he himself isn't napping.
C has taken to calling O "brother." (They actually both say "brother." I don't know if it is because everyone we meet says "brother" to them, but they call each other "brother" and call their older brother D by his name.) The other day I was getting ready in my bedroom, on the other side of the baby gate down the hallway. I heard C yelling at the gate (yes, I can tell apart their cries). As I came closer I heard him saying "Brofer! Brofer!" and pointing energetically toward the sunroom. I open the gate and he took off running as fast as his little legs would take him. He stopped in the sunroom doorway and yelled, "Brofer!" pointing into the sunroom. I walked in the sunroom to find O crying over a pile of stacking blocks. He was frustrated with the blocks because he was trying to stack together chunky Legos with Duplos. I helped O sort out his blocks, stacking the right kinds together. C squealed with delight, happy I helped O solve his problem, and then ran over to play at the train table. My sister said he was a toddler Old Yeller, "What's that, boy? O can't get his blocks straight?" It was adorable.
When we pray at the table, they must hold hands with each other. Toddlers sometimes have a hard time sorting out the logistics of things. "If I'm holding a fork and eating my dinner.... how do I hold his hand?" But they furrow a brow and either switch hands holding the fork, freeing a hand to hold their brother's, or they set the fork down all together to hold hands. They imitate each other. If one of them puts a napkin on his head, the other must do so as well; this leads to peals of laughter. If one of them starts doing a silly dance because he is excited about something ("Sweet! Bananas for breakfast!") then the other one does so as well. It is sweet watching them work together to stack blocks or make a train on the train table or struggle to take off each other's shoes.
Their imitation is not limited to each other. They try to do what their older brother D is doing as well as imitating me and their daddy. They get frustrated sometimes imitating D. He'll be hitting t-ball in the backyard and they can't figure out how it's done and really want to do it. Or he'll be driving the John Deere tractor and they can't reach the peddles (not that I would allow them to drive it! Yikes!). He also has lots of toys with small pieces that are so fascinating to them-- that I don't let them near due to choking hazards-- which endear the toys to them more (Playmobile playsets, for instance). They just always want to see what D is doing, if he's putting together a puzzle, or watching cartoons, or drawing at the table. They climb in the chair with him, follow behind him, snuggle up on the couch beside him. Sometimes it is too much for him, like when he's making a puzzle and they come over to kick the pieces around or climb in his chair making no room for him. They watch him while they are in their high chairs eating snack and scream to get out when he sits down with a toy. They also watch me and want to do what I'm doing, unloading the dishwasher, doing the laundry, making dinner. They cook in their little kitchen and bring over samples for me to try. If I sit down, they want to crawl in my lap. O will bring a book for me to read to him; C will crawl in my lap with his Batcho and suck his thumb while I read my own book.
They are helpful and sweet as well. When it is time for O's medicine, both C and D will get toys for O to hold while he sits with the nebulizer. The other two boys will put a blanket on O's legs; D does a dance to distract O on days that O just doesn't want to do the nebulizer. If one of the toddlers starts crying, someone will bring him his favorite blanket, either the other toddler or their older brother. When I sit down on the couch, O runs to the blanket bin and pulls out a blanket for me and tries to put it in my lap. It is very obvious now that they are aware of the other family members and not just themselves. They ask about the other family members that aren't in the room, Dadda when he's at work or Brother when one of them is sleeping, and seek them out when they aren't immediately found, "Dadda is at school and won't be home until dinner. Your brother is taking a nap and will be out in a little while." They pat each other and their older brother on the head when someone starts crying. They know what "gentle" means and gently pet each other. (My favorite is when they call each other "baby," like they aren't the same age...?)
We heard it a lot the first year, "How lucky they will have each other!" "So much fun to have a built in playmate!" Maybe those people were speaking from experience or maybe they were just saying that because our toddlers are twins. There are many days when the built-in playmate is just a built-in battle; toddlers are willing to put it all on the line for a desired toy. But then there are many days that they have someone to play peekaboo with at the check out stand or to talk to in their crib while I make myself a cup of coffee in the morning before getting them out. And while they do enjoy playing with their older brother, they have someone to play with who is at the same age level as them, a fellow toddler who's interests are the same. ("Let's not stack the blocks; let's throw the blocks.") You know, up until about 20 months it was pretty much like having two separate toddlers throwing two separate tantrums on me. Now at least they are two toddlers throwing a tantrum over the same toy or two toddlers throwing a tantrum because his brother wasn't doing what he wanted.
Other blog posts on twin toddlerhood: