What are some things that your son does do well and follow through with? What seems to motivate him with those things? Often children are observational learners and model behavior that they have seen. Is there a significant figure in your son's life that gives up easily?
Does your son have many friends? Is it possible to pair your son up with a good friend on a sports team?
With regards XXXXX XXXXX have you discussed the issues with your son's teacher? How is he doing overall in all academic areas?
There may be some underlying issue as to why your son gives up in many situations. He needs to develop greater confidence in his own abilities and more self esteem which is he truly lacking. It is possible that you could try psychological counseling. First if there is a school psychologist available, ask him/her to speak with your son. State your concerns first. If that option is not available, go through your health insurance. It is worth a try. Counseling could provide your son with the tools and techniques that will make him feel better about his abilities. You can even receive counseling as well to acquire intervention strategies in dealing with your son. Your son is still young. He has the potential to do great things in this world.
I hope that this has helped. If so, please ACCEPT so that I may be paid for my efforts. Positive feedback is appreciated as well. Have a great evening and rest of the week.