My husband is asking me to move to his hometown and take care of his ailing parents. While I don't want to run away from my duty as a daughter-in-law staying in a small town would not be good for the education of my six-year-old son. how do I explain this to my husband without hurting him?

One fine day, wrapping up your whole stuff and moving to another place sans your husband doesn't seem a good plan when you don't see any major reason as why the in-laws cannot shift to your place. Tell your husband that getting his parents to your place would be a better idea as that way you all can live together, else you will have to run two homes, one where your husband will stay and other your in-laws place. Also, your son who is in his formative years will have to live without the love and presence of his father which can easily be avoided if in-laws shift with you.