Giving each other comfort

When M moved schools it was a pretty good transition but he would visit T in her room for some hugs and smiles. Every time he passes her door she lights up and often times emits a high pitched scream of excitement. It goes the other way as well. If T is crying M will get her pacifier or blanket. But the cutest thing is when she is crying and he goes up and gives her a hug and says 'It's okay I'm here T.' It melts my heart every time.