Tom and Jerry do seem like friends and enemies at the same time.
On one hand Tom the cat is trying to harm Jerry the mouse while other times Tom helps Jerry the mouse out as well as Jerry the mouse helps Tom the cat out.
So from what I've seen I would consider Tom and Jerry Friends but they can also be enemies that love each other but want to fight each other.
In my opinion Tom and Jerry are friends and enemies at the same time but according to the show makers Tom and Jerry are not friends.