sleep time

There's this guy I know that neglected his puppy medical care while fully knowing that the puppy had contracted parvo. Roommates witnessed the guy would leave the puppy in the cage for so long that it would just sit in its diahrrea and hardly take him out. The puppy had a brother with parvo so the owner immediately told this guy about it and this guy completely ignored him. The pup suffered through symptoms to the point of bleeding diahrrea. When this guy finally brought the pup to the vet, the vet said the pup was too far gone and had to be put down. Six months later he buys another puppy... Based on the neglect for the pup that passed, I don't think it's good for him to have another life in his hands when he couldn't do the basic thing like take the pup to the vet when it was OBVIOUSLY sick/in pain in addition to the warning and urgency of the other owner. Ideally, I would like this puppy to be taken from him. Realistically, it can't be taken until it's too late and has been put through abuse. I was wondering if anyone knows what steps I can take to alert the proper authorities and get him on some type of alert/watch list for potential neglect? I know realistically they cant take the puppy he just bought with no evidence of neglect. It's also been a while since the pervious pup passed and the only evidence I would be able to provide are statements from roommates and the guy who warned him, possibly a statement of the condition of the pup when it came in from the vet if I try hard enough (probably not available to me though). (Also I tried to alert the seller about the previous neglect and they wouldn't do anything. I also tried to kindly advise this guy to reconsider having another puppy so soon and in addition to still being in school, but he didn't budge and said the overused phrase "Last time I checked, it was my life!") If you want to message me directly to talk about it, I would gladly appreciate the help!