While I am not aware of any official list that exists, they are at least the 33rd set of siblings that include at least one brother who at some point was an Islander.
Ryan is the only player on the current squad whose brother is (or was) an NHL player. (Coach Jack Capuano and brother Dave also fall into that category, although neither played for the Isles)
Other recent Islanders with brothers who played in the NHL include:
Adam Pelech (Mike)
Griffin Reinhart (Sam, Max)
Jay Pandolfo (Mike)
Mike Comrie (Paul)
Ryan Smyth (Kevin)
Drew Fata (Rico)
Marko Kiprusoff (Miikka)
Jamie Rivers (Shawn)
Taylor Pyatt (Tom)
There have been several brothers who have both played for the Islanders:
Mikael & Niklas Andersson
Mathieu & Martin Biron
Kevin & Kip Miller (Kelly)
Duane, Brent & Ron Sutter (Brian, Darryl, Rich)
Kenny & Jorgen Jonsson
Jean & Denis Potvin
Only the Potvins, Duane/Brent Sutter, and the Jonssons played together for the Islanders. The Anderssons both played for the Isles in the 1999-2000 season, but at different times. Kevin Miller was an Islander in between two of Kip Miller's three times with the team The Birons were Islanders nearly a decade apart.
However, to find the last time that an Islander faced his brother, you have to go back to Y2K, almost exactly. On January 2, 2000 the Isles faced Philadelphia with Mikael a Flyer and Niklas an Islander.
The Flyers won 4-1, and neither brother figured in the scoring. Ted Drury was also in the Islander lineup that day; he had faced his brother Chris earlier that season (11/19/99). While Kenny and Jorgen Jonsson appeared in numerous games together that season, only Jorgen played in that game.
Here's the list I have created of Islanders and their brothers. Can you add to that?
|Mikael & Niklas||Andersson|
|Martin & Mathieu||Biron|
|Gord (Peter, Kevin)||Dineen|
|Jorgen & Kenny||Jönsson|
|Kevin & Kip (Kelly)||Miller|
|Jean & Denis||Potvin|
|Griffin (Max & Sam)||Reinhart|
|Duane, Brent & Ron (Brian, Darryl & Rich)||Sutter|
Stephen Gionta, who appeared with the Isles in pre-season, also has an NHL brother (Brian) but doesn't make this list because he has yet to play in a regular season game for the Isles. Claude Lemieux would also have been on the list, but he was only an Islander on paper.