The name "Lincoln Dunwoody" is all over the wall. Holmes stares at it while Watson tries to talk him down. Holmes says there's no one in New York with that name. But if it's two surnames, the Lincoln Family has a long history of philanthropy, as does the Dunwoody Trust. The head of Lincoln just went down with CAA. Weird coincidence, especially since his family has no history of this hereditary problem. How about Dunwoody? Well, a woman named Greta Dunwoody recently retired and there's no further information. But the Trust just donated 20 million to St. Bede's Hospital, which could be a clue.
A woman plays piano as Holmes and Watson enter. It's Mrs. Dunwoody. She asks, "You're not my son, are you?" This is the universal symbol of "old person with dementia." She says has to keep practicing piano if she wants to get into Juilliard. Holmes notes that she still has muscle memory, even though her brain has decayed.
Brownstone. Holmes is cleaning out the refrigerator, because he's done with the CAA thing. And he's doing a very thorough job of it, even scrubbing at the shelves with a teeny brush. He won't tell Watson the solution, instead saying, "You're a detective, you tell me." I like this twist on their relationship. If gives Watson something different to do. Haltingly, she says that Carter Lydon has no apparent motive to attack the other two victims, so he's provisionally in the clear. All three victims are all rich people with charitable foundations, so maybe the idea was to encourage the foundations to donate money to study hereditary CAA? So it would be the smartest person at the company that studies the disease the most. It's Brian Watt! Of Watt-Helix! That's the genetics lab from earlier. His portrait was up on the wall. See, I told you one of these random names was going to be important later in the episode!