Transcripts of parish records for the RC Parish of St. Mary are included on the pay-website of the Irish Family History Foundation at
www.rootsireland.ie Select the Co. Meath county centre link, and make sure to filter by parish.. as there looks like there could be some duplicate entries.
Using the free search showed up a few possible Sheridan/Winters baptisms in the parish including a Mathew in 1856.
Do you have a birth cert for John ?
It should include his father's occupation, and may mention a more detailed address for the family - which could help.
Tracing forward is more complicated - unless you have clues as to later places of residence etc, it's just a case of following up possible leads in the area, e.g. possible marriage and death certs, census returns etc, and then gradually widening the search area..
Shane