From Wikipedia: Brandy generally contains 35–60% alcohol by volume (70–120 US proof)
Alcohol is unhealthy in general, especially bad for the brain and doubly so for a child's developing brain. So no, it's not recommended at all.
I (fortunately) don't know of any studies that gave children alcohol on purpose to test the effects, but known effects from alcohol exposure in the womb include facial anomalies, low birth weight, stunted growth, small head size, delayed or uncoordinated motor skills, hearing or vision problems, learning disabilities, behavior problems, and inappropriate social skills compared to same-age peers.
Of course a few spoons of Brandy will not cause all of that, but it shows that there are definite negative effects.
I'm not aware if the Brandy remedy is mostly used to sedate the child through the alcohol or if there are other benefits, but if there are, you could heat/boil the brandy to evaporate the alcohol before giving it.
Per the comment form @anongoodnurse, this is not a good way to get the alcohol out.