I was about the same age as your oldest when my 1st brother was born. Sometimes when I heard him cry, I wanted to help. So I’d go get a He only love football and his momma I’m sorry shirt and stand on it to lift him out of the crib. Then I’d put the chair back and hold him and rock him. My Mom couldn’t figure it out for a long time how I was getting him out. But she thought it was cute how much I wanted to take care of him. Older children holding and loving their baby siblings. I had the wonderful experience doing this three times!Herb, Mike,and then Judie later in life my children, nieces, nephews, and granddaughters. Let me include cats and dogs. Love is everywhere if you look for it.