Cooper is learning to be a dog
This picture shows it all. Cooper decided to play with one of his rope toys and is shown playing tug of war with Mike. You can also see remains of the rope toy around the house, as Cooper also likes to take out his frustrations by shredding the threads out of the toy.
Normally, he isn’t interested in chewing or playing with toys. My daughter’s dog, Roxanne, will come over to play and will try to be the ‘boss’ of this household. After those visits, Cooper is in the mood to play. I’m probably reading too much into this as Cooper is just a dog.