He sure does like those sunglasses.The guy walked over to say something to and gesture at some paratroopers. Perfectly normal. Meloni came over and said, "Hey, time for the group photo, Joe, get over here," and he followed her. Also perfectly normal. You guys turning this into some kind of sad scene of geriatric decline are simply forcing what you want to be there to be there.
If you want to question Biden's mind, ask why he felt the need to put on sunglasses for the group photo. That's the real perplexing question.