People who care for people with hydrocephalus are saints. How can I thank our son's caregiver?

Gratitude. Gratitude is expressed in many ways for caregivers. They receive a lot of satisfaction in that they are helping people on a daily basis- and your verbalizing that to the caregiver would be greatly appreciated. If you are compelled, you may choose some small token of gratitude such as a massage, a gift certificate, or other similar inexpensive gift as an external expression of inner affection.