If you are lucky this is the torque converter. If this is a Nissan with the CVT transmission then it is also possible that the transmission is screwed up in which case it will be a very expensive fix. Nissan is known to have really fucked up CVT transmissions that don’t last for shit.
If you were in the business of selling used tire then he might have some recourse… but because you aren’t a tire dealer you aren’t liable for anything. Only thing that would change that is if you had known of some defect and then done something to hide it from the purchaser.