Do I need to file I-601 for my dad's communist party membership?
-Not need it, but provide a statement (google to find the sample letter).
and he didn't disclose about military service when applied for Visa (2008) before,
-It does not matter to green card application this time.
will it matter if we disclose it this time?
-Yes, put it in the related items of Form I-485.
Thanks.