advice appreciated (adult dog potty training)

Let me give you a background of the situation:

I live with 4 other girls and two dogs. Neither is mine. One is a minnie snouzer (sp?) who is female and 9 months old and is perfectly trained. The other is a 2 yr old pomeranian male who is not fixed and pees in our house every chance he gets, and it is disgusting and irritating especially since someone other than the owner ends up cleaning it up most of the time. I honestly don't know why the dog does this, whether it is out of anger that his owner is not home with him very often (full time job), lack of training, or whatever. And I know the obvious advice as to what I can do would be to talk to the owner about the problems.The problem is that the owner is a very good friend, and it is awkward to address this issue with them in the sense that they get very defensive and upset if its even brought up, and I would personally rather live with this than have a falling out over a stupid dog.

Lately the dog has been forced to live outside the entire day the owner is at work, but if it gets too hot in the house we wind up having to put the dog in their room with the door shut so we can open doors for ventilation. I feel bad doing this. I am just wondering if there is anything I can personally do with the dog that isn't too time consuming (I have a life and responsibilities of my own afterall) that could maybe help the situation? I don't know if anyone else has had a similar situation happen and what they did to cope with it? Because I am honestly close to accidentally leaving the gate open and hoping it runs away I am getting so over this dog. Thanks!

The problem is that the owner is a very good friend, and it is awkward to address this issue with them in the sense that they get very defensive and upset if its even brought up, and I would personally rather live with this than have a falling out over a stupid dog.

It doesn't seem the issue is the dog here. The issue is that either your friend doesn't understand how inconsiderate it is to have her animal peeing all over a house that she shares with others, or just doesn't care.

Why does she have this dog if she's not home with enough, hasn't housebroken it, and hasn't even had it fixed? That's another thing, WHY is this dog not fixed? A dog is MUCH MUCH more likely to exhibit inappropriate peeing if it is not fixed.

I dunno how much you personally can do since you're not the owner and you're not the one that personally decided to take on responsibility for this animal.

If you'd like to try housebreaking it yourself that is an option, but this will take time and consistency. Crate training is the easiest, especially if you don't have time to be with the dog 24/7, but you're not the owner and the owner seems to lack interest so would anyone be willing to buy a crate?.
You can try housebreaking without a crate but the dog will have to be watched a lot more closely, so if it is in the process of having an accident you can tell it "no" take it outside and give it a potty command, then praise it for going in the correct place. Every time the dog does its business outside give it a treat and act really excited. Every time the dog tries to go in the house say "no!" pick it up or lead it outside and say "go potty" or any other words of your choosing. Just be consistent.
Any time the dog is allowed to go in the house and no one notices at the time the dog is learning that it's ok to go in the house. Punishing the dog after the fact will do absolutely nothing, so someone has to be watching the dog at all times.

If you can get your hands on a dog crate for training, then every time the dog does not go to the bathroom when you take it outside, calmly lead it to the crate and lock the door. 10-15 mins later take the dog back out and give the potty command. If the dog doesn't go, repeat. When the dog DOES finally go, give it a treat, praise it, act excited and let it play for awhile.
When everyone goes to sleep at night the dog should go in the crate to sleep until everyone wakes up. If the dog is left out at night obviously there's a chance it might have an accident.
The crate should be just big enough for the dog to comfortably turn around and lay down. If it's too big the dog will just go to the bathroom in the corner where it won't have to lay in it.
DO NOT EVER release the dog free in the house without supervision. This will only teach the dog that it can eliminate in the house especially when no one is looking.

EVERY SINGLE place where the dog has eliminated on the rug needs to be thoroughly cleaned with a non-ammonia based cleaner so that the smell is no longer there and the dog isn't tempted to go in those spots.