If a husband and his wife are very mad at each other, they are ... ?
I mean, if you see a couple in a mall brawling at eatch other they are ... ?
If a car bump into an other one and both of the drivers fight verbally, they are ... ?
For this part of your question, "fighting" is correct. There are other verbs that would work: "quarreling" or "arguing" or even "bickering". These are good verbs but you could also use nouns. "The drivers are involved in an argument" "...involved in an altercation", "...involved in a squabble". Hope that helps!