Take him to a vet to rule out any physical causes for this change in behavior, pain, discomfort and various diseases can lead to major shifts in a cat's personality turning them 'mean'. once you rule out physical causes, you have to go with the notion that he is just in a fowl mood and you will need to re socialize him - or get him used to being touched. 'Force' him to play time. Force him to accept human contact. The longer you wait the less likely he will be to take to tolerance of human contact, further if you let him have his way in this, it could lead to a cat who suffocates babies, scratches Nana, or other vicious things which lead to a cat having to be let go or put down. This may mean having to get a pair of leather gloves (and other protective clothing) get down on the ground, and hold him down while you pet him at first for about five minutes, slightly longer depends on his reaction. do it once or twice a day, gradually increasing the time you spend 'holding him down'. Through this you are being calming, gentle and kind saying nice things in a nice tone of voice to let him know you are not going to hurt him. Unfortunately you cannot have a sit down chat with the cat to find out what is emotionally upsetting him, so you are 'telling him' with gentle 'force' which is the only way in most cases to resocialize a cat. Prior to the training you will take him to a vet to get a check over just to make certain there is no physical cause for his temperament change. Rewards of cat nip, caat treats etc may come in handy, especially when it finally gets to the point where he will lay there - maybe growling, but you want to affirm his 'good behavior' as much as possible. It is probable that he will never be a cuddly ball of fur, but you still need to instill in him the pecking order that humans are at the top of the chain of command and he is at the bottom and that he must accept attention from humans, or at the very least flee without attacking the human.