This is a big problem that is not easy to solve. You must establish yourself as the pack leader and you can research this online. Establishing yourself as the pack leader will involve obedience training, always asking the dog to do something BEFORE you give them something like food or a pat on the head etc, always going out of doorways first, never let him sleep on the bed, never doing what he ask such as don't give him a treat if he is whining for one, or getting off the sofa if he tries to take your space. This will take several months but it will work.
In this case, the older dog is clearly the pack leader as the other one will follow him everywhere. Once you are a secure, strong pack leader, both dogs will follow you because in their minds, you will know what is best for them and will protect them. Right now, they think you are weak and weakness is useless in the canine world because you will lower their chance of survival. Therefore they do not obey you and will choose to do whatever they like. You must show both that you are the pack leader without being aggressive or angry as they will not respect you otherwise but you do need to show them that you mean what you do.
After establishing yourself as the pack leader, and if you still find him still running away, it would mean that his behaviour has been so ingrained that it has become a habit. If this is the case, you will need to train him to follow you by purchasing a long lead and getting some really nice treats. Make him follow the treat and at the same time walking away, telling him he is a good dog and getting him to walk to "heel" by your side. Until you can trust him, you cannot let him off leash otherwise you go back to square one. And without establishing yourself as a pack leader, he will still run away as he will never obey you.
If you are disagreeing because sometimes he does obey you when you tell him to do something, this is because the command has been deeply ingrained and has become habit, not because he is obeying you. I hope this gives you some insight and good luck in reading more about dog psychology to improve your dogs behaviour.
And remember to be calm when training, not be aggressive and always make sure you get him to do what you want him to do by using tools like long leads if you need it.