D&D 5E How do you handle a hunting dog/war dog in combat?

[Flamestrike]

I wouldn't let them use the Help action as it is not in their stat block

It doesnt need to be.

I'd have no problem with a dog taking the Help action for certain tasks.

Tracking/ Searching being the main one.

 

[aco175]

I feel that it needs to be something less than the ranger ability or a familiar. Most of the time, I allow the dog like this to defend itself and attack if the PC makes a handle animal check. I use the flanking rules and the animal would count as an ally for the sneak attack of a rogue.

Pets of PCs can be a different classification. They have an ability to disappear when in danger, as long as they are not allowed to attack or aid in combat. The urchin's pet mouse never is hit with a fireball, but if the PC tries to throw it at a mage to disrupt concentration, it is fair game.