Hi
Not good news I'm afraid.
If he had been In Jersey during the occupation, he would have had to complete an Occupation Registration Card. Sadly, there is no card (for either Newman or Newmans. Your title differs from the text).
I next looked to see if he had been sent to a camp in Europe. There is a complete list for all Channel Islands in the book "Islanders Deported". Again, thankfully, there is no such name. The nearest was an Ernest Newman.
The conclusion for Jersey is therefore that he left before the island was invaded but to where I have no idea.
Hopefully someone from the other islands will pick up this posting.
Stewart
PS Could he have served somewhere in WWII? It may be worth checking the military records.