Alex loves his little brother, always wants to hold and hug...and squeeze...and poke...him.
I think he looks upon him as a sweet and adorable science experiment, as in, "I wonder what would happen if...?" A couple days ago, I left the two of them alone together for no more than 20 seconds so that I could grab a basket of laundry to fold, and when I came back, Alex informed me proudly that, "Isaac has a hole in his head". I panicked and immediately Googled "fontanelles" to make sure that he hadn't done any permanent damage (it seems we sidestepped that landmine), then spent the next ten minutes lecturing Alex on how he may not touch Isaac's head without asking Mom or Dad first...nor may he explore how far backwards his little fingers bend or how much air Isaac can get when flung out of his bouncy seat.
While his efforts to be soft and gentle often go awry (a la Lenny from Of Mice and Men), he is very affectionate with Isaac, giving him hugs and kisses and generously doling out "I love you's" in a high-pitched, baby-friendly voice. He likes to shows Isaac all of his toys and demonstrate how they work, despite the fact that Isaac is mostly oblivious. He has been so helpful, plays by himself when Isaac needs to be fed, and fetches diapers and Boppys and burp rags when I ask.
He is a great big brother, and I know Isaac will be a great little one. I think I'm in for some crazy times ahead with these two.