It's been a while but I know exactly what Comet and Blitzen would've done.
Comet would get a lifetime supply of timothy hay and paper bags, spread out over an entire room so he could have everywhere to explore but also, paper bags and hay. Regular deliveries of watermelon, blueberries, baby cucumber, spinach, lettuce, salad leaves (and more spinach, and more lettuce), parsley and thyme would round out the food. THEN he'd need a Minder, because what if his spinach leaves were the wrong way round? Can't have that, need to make sure someone could make sure he gets the stalk part of the leaf first.
Blitzen, on the other hand, would order himself a couple of carrot cottages instead of paper bags, but basically the same idea. Buy all the same hay and food, along with mint, coriander, kale, spring greens - and then he'd obviously get all of his and all of Comet's share too. Who needs friends and family when you can have all the food, huh? HUH?