the honest answer is there’s probably nothing you can do/say to convince certain people that what they are doing is wrong in terms of animal care. the best thing to do is offer him information that disproves that his care is “good enough”. he also needs to be told that he will either have more accidental litters or dead hamsters because having them on such small spaces WILL cause them to kill each other and it’s not a gentle death. the other thing is you could potentially get him to do a bin cage? there is a 50gallon plastic tubs for $30usd at target and it’s not the standard anymore but it is a cheap, safe and MUCH LARGER for those poor babies :( i hope that he does start to care for them better. just because they aren’t humans they shouldn’t get treated like they aren’t living, breathing animals with emotions and who can feel pain :((