it was never confirmed as later, it was found out that neither Bride or Lightholler actually saw Phillips on board collapsible B. There is also mention in Brides testimony that when picked up by Carpathia, there was a dead officer which he claimed to be Phillips. Once again that is unconfirmed, Col. Gracie, stated that he saw the dead officer and confirmed it was not Phillips.
There's a good chance that Phillips made it to the boat, he probably collapsed and drifted off some time later.
Interesting fact: Phillips is quoted as saying to a friend that his third wreck would be the death of him ( I'm not sure what the previous two were) also, he had a fear of icebergs.