If he plans to stay in the Marshall's, no big deal. But if he heads SE from there he's really going to need weather
info on the fly. Typhoon season starts in May and the typhoons generally starts building out around the Guam
area, and to the South, and work their way towards the Philippines crossing the Philippine Sea.
Typhoon season lasts until Nov. but storms still come in as tropical depressions. The last one came in Nov. 2nd and slammed the Semirara Is. as a Cat 5 and died down on it's way across the Visayan's. By the time it got here in Cavite it was just a windy day (25 kt.).
The best times to sail to HI is in the spring, or catch a opening in Nov. after the Mexican storms die down.