I am trying to write an early Cold War-era (late 1940's) story in which a family from a Soviet republic -- actually a fictional one but I am basing it a lot on Poland -- is trying to get to the west. There's a father and mother, both in their early thirties, who have a few month old baby. There's also a 60-ish year-old grandma, but she's kind of irrelevant for the question. I am thinking that the father, who was with the Resistance during the war, would have some experience with whatever this anesthetic is to make his baby sleep through their border crossing, or if he didn't he'd certainly know someone who did. I'm looking for something that could potentially kill the baby if administered wrongly. Of course, the father won't tell the others that this is a risk, and the baby will actually be fine, but the mother will be troubled by this whole scenario and once they are safely in France she will do some research and discover that there actually was this risk, and the story will basically be about the conversation that the couple have once the mother finds out that her husband put the life of their child at risk and didn't even consult with her.
So, basically, I would like to know what kind of anesthetic it would be, and how would I find out what a safe dose would be and an unsafe dose, or the specifics, whether it's more based on chance or the individual's body. I really don't know how to research this right. I looked up chloroform on Wikipedia but all I learned was that it is only administered through breathing it and besides the use in the films of people slapping a rag with chloroform on someone's face isn't really realistic. I looked through their list of anesthetics at Wikipedia but there didn't seem to be this specific info. I also looked in the tag medicine: drugs here at little details, but those posts were mostly about treatment of illegal drug addiction and overdose, which isn't what I'm looking for.
Thank you so much!