Hi Anna,
From what we have learned about Boots, whether to get a siamese cat or not, depends on what type of house cat you want. Does your dad want a cat that loves to be held and cuddled? Does he want a cat that pretty much stays on the floor and does not climb up on high pieces of furniture? That loves to be brushed and has a sweet personality. That eats most cat food without complaint and comes when called, then don't get a Siamese.
Does he want a cat that is intelligent and devilish. That climbs high on things and will climb the curtains if not declawed. And only wants held if he is in the mood, plus loves to knock things down and chew on houseplants and any nice decorations. If told not to do something will return to do it again and again, just to upset you. Can be playful one minute and biting your hands the next, then get a Siamese.
This has been our experience with Boots. He is only half Siamese and his dad was another breed. But I had a friend in Florida, that had 3 Siamese. I cleaned house for her. Those cats got up on top of her kitchen cupboards and used that area for there potty. One would get up on her kitchen counter and spay urine, on the food canisters, if she had yelled at him for bad behavior. A cat that is intelligent enough to get even with his owner is too intelligent for his own good.
This is not to say that all Siamese cats have these traits, but should I ever have another cat I would not pick a Siamese cat.