You can see drained nodes with condor_status.
For nodes that are down, that is a more difficult question – I'd do it using an external means.
I’m used to torque, in which there is a “pbsnodes –l” command that displays nodes that are down or drained.
Strangely, I don’t find how to see this information in condor : what would be the condor way of finding this information ?
I’m sure this can become hard when the pool is dynamic, but even then there must be traces of nodes which belonged to the pool “one day” or in the last X days ?