My son has been hospitalized with diabetic gastroparesis 5 times in the last two years and has constant cramps and nausea; any hope of a recovery?

Recovery time varies. Recover time will vary depending on many factors including age, general health of the patient, infection control, blood sugar control, and follow up care.
Control blood sugar. The key is good control of blood sugar. This is usually a complication of uncontrolled long standing diabetes. Monitor his hba1c and keep it below 7. Avoid fatty foods. Certain medications can be used as well to promote proper function of the stomach.