Welcome!
I have an adopted male Pom (?)
I got him when he was about 3 1/2 years old and have had him for 18 months. We were told he is a Pom but he is a lot larger than a normal Pom, wrong colour and has less coat:
Lewis
Lewis is my only experience with Poms so I can only go by him when talking about them (and he is not typical) but this is some of my observations/advice:
For grooming all I do (in addition to normal dog maintenance) is brush him all over at least once a week (takes about 15 minutes) and trim his feet when they look hairy. He never has knots now.
I have a photo of what I do with his feet:
So just trim the fur out from between his pads and neaten up the top. You don't have to do this but I like Lewis to look tidy.
I don't trim anything else.
The main area that it is importance to groom is the back legs, that's where Lewis has the most under coat anyway. When we got him his back legs were a bit of a mess with a lot of undercoat that was a bit mated. Also, he had some dreadlocks behind his ears.
What condition is your dogs coat in? and how does he respond to grooming?
When we first got Lewis he was not used to grooming so I had to take it very slow and watch his face the entire time to make sure he wasn't going to bite me (he never did). It took weeks to get all the undercoat out of his legs.
Also if you bath your dog make sure you get all the undercoat dry. I would recomend using a groomer as they use a powerful dryer to help get the undercoat out and you wont have fur all over your house. If your pom has his full coat then don't let any groomer shave him (unless his coat is all matts and there is no choice). They have double coats that are not meant to be shaved. If you shave a pom the coat might not grow back properly meaning it could become harder to keep knot-free and shaved fur looks duller.
For temperament:
Lewis barks a lot (a lot).
He's definitly become a one person dog (mine).
Can be a little protective over me.
Very affectionate and cuddly with me but does not like strangers touching him.
Your pom might not bark much now but don't be surprised if he finds his voice later.
Other things to think about:
Teeth: Lewis had horrible teeth when we got him but they are better now that he gets fed better food and has treats that help his teeth. I brush his teeth when I groom him.
Poms have delicate necks. If your pom pulls on lead at all then use a harness, many use a harness even if the dog does not pull.
Since Dangerfield is a rescue he might not have had much training. Lewis was like that, but he has since proven to be pretty smart. I'm doing obedience, rally-o and agility with him, he is coming along really well (especially in obedience, he's really good). Maybe your son could get into training him.