I'm glad to hear it's nothing serious!
As for his former owners...they loved him so much that they let their faithful 6 year old family member sit in a kennel for 3 months? They couldn't even wait to find him a home!
I'm sorry, but this is outrageous, and "having a baby"is at the top of the list for why people dump their pets. Very sad.
I know it's hard for good pet owners like you to imagine people doing such a thing, but it happens all the time, and it's always the same: "I just LOVE Fluffy dearly, but of course I have to get rid of him now that I have a baby/new job/am moving, blah blah blah."