That's one big dog. Looks larger than our Rotten Shepherd, a 95 pound bundle of love. I'm the only one who plays rough with her, but I'm leery of what she's capable of if we go too far, along with the scratches and bites that go with it. She's drawn blood a few times, nothing serious.
She's as gentle as can be around kids.
That is too big a dog for a 78 year old man to be "playing" with. I'm in agreement with other posters, who said the fall was due to dementia.