Does he have a viable opponent? This is the kind of seat that falls if Trump collapses.
It looks like the two Democrats running seem to be holding up alright. This is from the FEC:
2016 PRE-PRIMARY: Total Receipts, Total Disbursements, Cash on Hand
-Lee Zeldin (R) - $306,281, $248,670, $1,791,239
-Anna Throne-Holst (D) - $274,358, $728,859, $660,447
-David L Calone (D) - $170,041, $575,895, $500,675
Calone was endorsed by NYT I think, but Anna Throne-Holst was endorsed by a ton of big name Democrats like Sen. Gillibrand and a bunch of NY representatives.