Unfortunately, rather than giving him away, i wouldn’t be surprised if we find out later that the he handed the dog over to the local pound where he might have or not been adopted out, or through carelessness on his part the dog died in his care. If his friend had sold or given the dog away, phone records from that time are usually available online on your personal account for 1 year (mine are, though I know companies differ). That being the case the number of the person he handed the dog to would be retrievable and then the dog as well from whatever phone company he used. That goes for land lines not just cells. If the guy says he can’t get those phone numbers or he never talked on the phone or texted with those people then he’d know his friend did something else which probably resulted in the death of his dog. Very sad.