John Feehan received a Civil War pension (Company D, 17th PA Cav): Appl 411,423; Widow Mary: Appl 573,762 Cert. 383,066.
You can get a copy of his pension from the National Archives in Washington, DC for $75. While a bit pricey and the genealogical data it contains is uncertain, it may have some of what you are looking for. As I understand all the pensions will eventually be online, but I don't know the timeline. Some are already available online at Footnote.com for a fee.
I know you said you have his military file, but I don't know if you have the pension file which is usually much more helpful.
The Historical Society of Pennsylvania has a large selection of Philadelphia records. If John or Patrick were to inherit anything as minors they may have had guardians appointed. The Philadelphia County Orphans Court would have the record.