If he’s passed, search the Social Security Death index. If he’s in there, that will give you the social security number. You can then use that to order an SS-5 if necessary which should have his parents names. That’s not free. But you can search the SSDI for free here: https://www.familysearch.org/en/search/collection/1202535

I have looked them up but I really don’t want to pay for it.
Thanks –

The best place to start is asking your living relatives for any information they might have. Once you know some info on the next 1-3 generations back (your grandparents or great-grandparents), you’ll be able to find more information in public records and shared family trees (which generally won’t have info on anyone who’s still living). For that, you could start with free sites like FamilySearch.org. I wouldn’t recommend paid sites like Ancestry.com until you’ve found more to work with at free sites and you have a better feel for what type of records you want to look for. Then when you’re ready for that increased access, it’s worth trying Ancestry.