I think there is probably enough intel that the Senior Council might know Thomas is Eb's grandson. He is the ONLY son of the White King, that makes him significant. They'd try to look into him, why is he allowed to live. And his mom likely turns up. Eb may know, but not know Harry and Thomas know. Eb may even have been unaware, but when Thomas and Harry started to hang out, he looks Thomas up...
Here's a possibility - maybe Maggie is not the LAST person he lost to the Whamps. And she involved herself with them. Hardly totally innocent. Maybe they did take his wife.... and it was not Harry's grandmother. We spoke of his wife, and hear about Harry's grandmother... She died over 200 years ago. Could he have had a SECOND (or more?) wife in that time frame? Maybe even when Maggie left Raith, they came looking for her... went to his farm... and killed an innocent? And that the fresher wound?