Re-educating the Loman family would be quite an undertaking. Their problems run deep and have existed for as long as their family has been a family.
Happy's energy should be redirected from continually chasing women to engaging in some activities that require him to put his personality to good purpose. Teaching Happy to live in reality instead of ignoring it also would be helpful to him.
Biff needs to understand why he has lived his life as he has in order to live a more meaningful life. His idea that he is "a nothing" because he has failed to live up to his father's expectations should be challenged. Biff has spent a lot of time examining his life to arrive at the idea he is worthless; he should examine his life again, this time considering that he had grown up with a set of corrupt values. Although he does not realize it, Biff's life is not over; he has time to become the kind of man he--not his father--would admire.
Linda's re-education should focus on her own personality and role as wife and mother. She must come to understand that denying reality does not make it go away, that it is better to face a painful reality at the time rather than deal with it later. As a wife, her role should be to challenge her husband's decisions when she thinks they are wrong; as a mother, she should correct her children instead of making excuses for them and enabling their destructive behavior. Linda needs to learn that being weak and compliant is not demonstrating love; it is only being weak and compliant. Also, Linda must learn that she does have an identity other than Willy's wife and her sons' mother.
Re-educating Willy would require helping him understand that times have changed and that what used to work for him in his career will work no longer. He should find another line of work if he can't make the adjustment, rather than continuing to curse the system and live in the past. More importantly, Willy needs to reassess his values and develop some personal integrity; succeeding at any cost is an illusion. There is always a cost. Finally, Willy needs to understand that his value as a human being is not dependent upon how much money he does or does not make. He needs to spend more time doing those things in life he really enjoys, such as working on his house and his garden.