@Head_Trip
First, I'm unsure how long ago this was, and in which country. 40 years ago, suppositories were more commonplace than today, and even more so in some countries (e.g., France). Also, it was generally considered appropriate for older females (relatives, kindergarten staff, etc) to have children disrobe and to provide care to them, whereas today one would need authorization from parents or calls to professionals (e.g., it used to be the case that school staff could give Valium into the rectum to children having epileptic seizures, on doctors' prescription, whereas today they would just call emergency services). Rectal temperatures were more common, in part due to technical limitations on thermometers (an oral temperature required being able to hold the thermometer for 3 minutes).
It also depends on the arrangement between the parents and the grandparents : were there instructions given regarding care in situations of illness ?
That said, I recall watching this testimony of a woman whose grandparents submitted her to unnecessary enemas as a child. As she said, she had never particularly suffered from constipation or other bowel issues, yet was given enemas when staying at her grandparents'. It sounded like she had been abused.
https://www.youtube.com/watch?v=JQr3hsEQmbM
The phrase in French is “maternage abusif” or “nursing pathologique”, unsure in English. It designates acts, often from older female relatives or acquaintances, that are often presented as motivated by hygiene or medical needs, but that are in fact motivated by the sexual enjoyment of the caregiver. These include washing of the body, especially genitals, at an age when the child would be perfectly able to wash himself or herself; unnecessary intimate examinations, rectal temperatures, suppositories, enemas, etc. The key phrase here is “unnecessarily intrusive”.