Ok, I have elderly neighbors.. they are lonely. They say hello, walk over, stop by with baked goods, and take pictures of the kids on Halloween as they are trick or treating...
Is that creepy? No.
I personally don't have a problem with this.. This guy seems very cheerful in his position. I would love to have the custodian greeting the kids, and realizing that they are Not "just servants" as well.
I worked at an elementary school camp, and the custodians were great to the kids and to us. They loved "Mr. Matt", and they would invite him to have snack with them. We were there, and and Mr. Matt was fantastic to the kids. He just loved being around the kids, and had fun with them. He didn't do camp activities, but if he was doing something near the room (ie landscaping, or whatever).. the kids would watch. If it was near snack time, they would always leave snack for Mr. Matt. He would come by, eat a cookie, and chat with the kids for a few minutes.. do high fives and leave.
I think some either a) don't have kids, or never had them b) have grown kids, and miss the little one c) don't see anything wrong with sitting with the kids
At our school the aides sit with the kids, and same with the student teachers. Would it bother me if "Mr. Matt" sat with them as well? No it wouldn't.
Mr. Matt even does work on the side for some families around here.