“It is one thing to demand to have your lawyer present for questioning (surely a good idea); it is another thing to refuse to answer questions.”
I think that the NTSB has allowed him a little time to “recover” before any questioning. Common sense says that the officials don’t want to do anything that could later be used against them by the engineer for not “respecting” his situation right after the accident. Trying to talk to him too soon and he could claim to have been intimidated.
It also give them time to get his lab results and phone records. Not to mentiin do a complete background check.
Also time to interview his team on board the train. Get all of their stories before questiining him