Translation:Those experiments also made her lose her mind.
not sure, the lui here before the verb means that the person is the indirect object, so maybe this could better be translated as the:
"these experiments "that" were done on/to him, also made him lose his mind*"
*or rather caused his mind to be lost.
just my take on it though, may be wrong
Is the French sentence really correct? I don't understand why:
it has "faisaient" and "fait" - surely only one of these is needed?
The translation is in past perfect, when "faisaient" is imperfect?
Is it meant to be "ont ... fait", or just "faisaient"? Or there a nuance here I'm missing?
Duolingo seem to have decided that both preterit and present perfect could be translated either by passé composé or imparfait.
Which can work in a number of cases, but not all sentences proposed.
In the sentence proposed here, "made" can be translated to "faisaient" or "ont fait", since we have no context to understand whether the action had a certain duration in the past but is finished at the time we speak (imparfait), or whether the action started in the past and is still valid at the time we speak (passé composé).
If you read the whole thread, you will see that there is a mistake in the French sentence: the word "fait" does not belong to that sentence.
For the rest of the construction:
you will notice that "lui" (meaning à+il or à+elle) is placed in front of the verb unlike in English.
and that "aussi" is after verb "faisaient" unlike in English where "also" is placed before "made".
"perdre la raison" and not "sa raison" is the way the French refers to body parts (no possessive).
note that instead of "la raison", you could use "la tête" (head) or "l'esprit" (mind)