Following info from 1930 Totowa, Passaic, NJ Roll 1382, Enumeration District 177, Image 2650:
TITUS, Peter R. age 52 b. NJ Father & Mother b. NJ Mary, wife age 48 b. NJ, Father b. Eng, Mother b. NY Vivian,dau.age 24 b. NJ Eileen,dau. age 7 b. NJ
Peter's occupation U.S. Customs, Veteran of WWI
1910 Manchester Twp., Passaic, NJ Serial T624, Roll 907, Part 2, Page 51B TITUS, Peter R. Mary E., wife *Mary V., dau. *Since Mary V. doesn't appear on the 1930 census, she may have married or died.
Peter's occupation: Weigher, Port of New York.
Since Peter was born 1877/78, he could very well have been in the Spanish-American War (1898).He would have been 20 years old.
You can get copies of above censuses from the Family Library at the Latter Day Saints (the Mormons) for a nominal fee.You should also obtain copies of possible pension records, since he was in both wars.
If you have the letter sent to Peter by the president, you should contact a professional to preserve it.DON'T make copies from a copying machine.The light will destroy the integrity of the letter and darken it.(Speaking from experience.)