Hi Andrew,
I checked the two pension indices (by name, on Ancestry, and by unit, on Fold3), the 1890 Veterans census, and the index to compiled military service records (on Fold3). He's not in any of them.
So I suspect he didn't serve in the Civil War, but was a civilian physician who evaluated John to prove he was eligible for a pension.
I checked Newspapers.com and GenealogyBank without finding an obituary. He's not in the Directory of Deceased American Physicians 1804-1929 (on Ancestry at https://www.ancestry.com/search/collections/7833/), or the US, Deceased Physician File (AMA), 1864-1968 (FamilySearch, https://www.familysearch.org/search/collection/2061540).
I gather the Saint Albans' Messenger (from St Albans, Vermont) is one of the papers that covers Malone. Newspapers.com has it, but is missing 1895-1899. GenealogyBank doesn't have it. GenealogyBank has the Malone Telegram from 2008 until now, and it started only in 1905. Newspapers.com doesn't have any newspapers from Malone.
He has a FamilySearch profile (https://www.familysearch.org/tree/person/details/KZCQ-53D), which at least lists census and the NY death index.