Hello - I am Dr. Matt - I would be glad to help you with your question.
I am sorry to hear that your cat has become quite stressed from your grandbaby visiting. This is quite common in cats as they do not like changes very much. Trying to reduce the stress levels can be challenging though there are some ways to try to reduce the stress that he is feeling.
One suggestion would be to purchase a product from the pet store called Feliway. This is natural pheromone that cats release from the scent glands in their cheeks that is quite relaxing to cats. Feliway can be purchased in a diffuser that can be plugged into a wall in the rooms that he seems to stay in the most or as a spray that can be sprayed in the rooms that he is in 2-3 times a day. Here is a link to the website:
Another suggestion would be to try to make the times that your grandbaby is around your cat positive. This can be achieved by giving your cat some toys that will encourage him to play or give him some special food
such as canned food. If he really likes canned food then only feed this to him when your grandbaby is around him. Most cats will then start to associate this with the situation reducing the stress levels. I would also look for some toys that dispense food for him such as this:
The last suggestion would be to give your cat some areas which your grandbaby cannot get to which are "safe" for him. Cat towers and claiming perches are great as most cats will enjoy being up high observing what is occurring down below and as long as no one can touch them they fell much safer. You could purchase a cat tower from a pet store though any piece of furniture in which he can be much higher in the room is just fine.
Hope this helps to answer your question - if not or if you have any more questions please feel free to reply by clicking on the "reply to" button. Thank you for your question.