Is it possible to train a 5-yr old male to stop relieving himself in the house? He get scolded when found doing it, but to no avail.

It's possible - but you've got to work at it and give him a chance of finding out what you want him to do instead - treat him like a puppy - take him outside (go with him and stay with him) every time he wakes up, eats, plays, and make a big fuss and reward him (with food or a game with a special toy you keep just for training) each time her performs outside. Try and ignore the mistakes inside as telling him off will only add to his stress (which will make him more inclined to go inside because he feels safer), but if you do catch him in the act - clap your hands and distract him and encourage him to go outside with you to finish off - then reward him.........

My situation not the same as yours but
I'm doing exactly what Digger suggested with my soon to be 15 year old Vizsla who has always been clean in the house but now unfortunately he is not able to control his bladder properly so I'm treating him like a puppy, taking him outside whenever he gets to his feet, eats, drinks, even waking him up and making him go into the garden if he hasn't been out in a while.
Praise him up when outside and just accepting the accidents in the house - he's not his fault.
Hope you manage to house train your dog soon
Steph

Like digger says rewarding is the most beneficial way to train . Our pup goes out and now automatically looks toward the cupboard where his treats are left . :)
Have you had the dog since it was a puppy or have you only recently homed it ?
lel