are dogs the best comfort animal after a parent dies, are pit bulls/american staffordshires loving and cuddly?

Cats are way better and are known for lowering blood pressure and stress levels. Pit bulls are not a good comfort you would likely end up joining your parent if you get one, since it could turn on you and maul you to death, or it could maul a child to death. A fighting dog (which is what a pit bull is) does NOT make a good pet. You would be better off with a cat, and a Golden Retriever. Golden Retrievers don't attack kids and are sorties.

Yes, they are good comfort animals.  Some pits are gentle dogs.  If you have a dog & not going out to get one, I'm sure your pit would be concerned about your state of mind & know how broken your heart is.  Dogs are pretty intuitive about human emotions.

Pit bulls will give you it's how you train them  cuddles. 

The best pet to own, whether you've had a death in the family or not, is whatever species best fits your lifestyle, and that you have the funds, ability, and willingness to care for properly. For some people, that may be a dog. Others will find a lower maintenance pet will suit them better. A pet that is not a good choice for the specific person or situation can certainly add more stress than they relieve. 

As far as pit bulls, they can be good pets and very affectionate towards their owners in the right sort of homes. That generally means a home with no other pets and an experienced and active dog owner who is willing and able to manage a dog that is likely to exhibit some degree of dog aggressive behavior.  They are a lot of dog to own and often not a good fit for the average dog owner.