Not to sound like a concerned Mom giving lectures
but Puppies shouldn't have free roam & be allowed to play all day. They can get hypoglycemic attacks. Good thing your niece caught it in time & gave Kimchi some nutrical. Does she have a crate or an ex-pen set up w/a bed, water bowl, some toys, etc? Somewhere she can be confined safely.
I'm so scared of kidney disease (renal failure, my Grandfather passed away from this) & it's one of those organs that can't repair itself. Since kibble is lacking moisture, when I fed my guys kibble, I always moistened it w/hot water to make it soft. I added a table spoon of canned food or plain boiled salmon, turkey, whatever protein I had I shared w/them. I did this bc Momo wouldn't chew his kibble, just swallow it whole & that couldn't be good for his tummy.