Given that the aliens were able to manipulate Picard's mind, it's likely that they'd also have the ability to make sure that he isn't significantly harmed by what happened...
How could they accommodate for every variation of humanoid, vulcanoid, klingonoid and every other -oid out there?
The fact that they sent a probe with no manual, that was self-terminating and included only a flute shows me that these people weren't all that bright.
Instead of putting their accumulated knowledge into something tangible they download a snippet of it into someone who will die at some point and the whole of their culture will die with them, except for the flute and a dead probe.
It's nice in concept, but The Inner Light
wasn't a very well thought out episode. In my opinion.
The very fact that it worked with an alien brain shows that they must have some kind of brain-scanning capability.