Everyone is right, however you asked is it bad for him, if you mean physically or mentally no he will be just fine living in your pasture eating grass his hole life. But like everyone here has told you a trained horse is a a useful horse and untrained horse is no better then a cow. If you have been on him and he did not buck or freak out your could
consider the idea of learning a little yourself and training him yourself. I know I know I KNOW! Everyone this is not the BEST idea, but people have done before and horse turn out fine. Again its not best put it is doable. Keep it simple get him walking and stopping forward motion. Horses move into pressure teach him to move away from pressure. Apply pressure and remove the pressure when he response correctly. GO SLOW, remember you are learning at the same time as he is. You are going to make mistakes but if you have been on him and he excepted that you might be able to make him usable. A trainer would be better and faster. But its not impossible for you to train a horse yourself. Every one of us had a first horse we trained. And if I went back in time to train that horse again would I do things different/better? Yes and so would everyone here that trains horses.