Hattie: There is probably no pat answer to your question. The wounded were transported back to the States via different modes. A lucky few were flown back, some other lucky fellows were transported aboard hospital ships while most were returned on troop transport ships. Considering that this fellow was a fairly high ranking officer, he might have gotten a little better treatment than the average PFC. That aside, since the distance from Saipan to New York is roughly 7800 miles and transport ships of the day topped out at 23 knots then you can figure under the very best of circumstances at least 2-3 weeks but you need to consider a bunch of other factors:
1)You don't know how long he might have spent in a Saipan hospital. he could have spent days or weeks or longer before leaving. 2)You don't indicate the mode of transport but let's assume it was by ship, so: 3)Once he began his return, you don't know the route or schedule - did the ship stop somewhere else? It could have made several stops of unknown duration. 4)You state that he was interviewed in a New York hospital which causes me to wonder about something. I can't imagine that wounded from the Pacific theatre would be transported through the Panama Canal, into the Caribbean Sea and then up the east coast of the US. To my way of thinking, the wounded would have more likely disembarked in California. From there they could have been transported by train or possibly air to the east coast.
Obviously, this officers service records would probably provide the information but there are restrictions on getting them. I think Navy and Marine Corp. records were spared in the 1976(?) fire but Army records were devastated. Don't quote me on that, it has been a long time since I checked so I stand corrected.
I'm no expert in the transporting of WWII wounded so don't take what I say as gospel. However, I wouldn't be the least bit surprised if it didn't take at least a month or more. Perhaps someone with actual experience or more knowledge will come to your rescue with a better answer.Rick