My and My Parent's GC sponsor revoking sponsorship

[New_Applicant]

Hi,

My Uncle (who is US citizen) had sponsored my and my parent's green
card. My uncle wants to revoke his sponsorship to our green cards.

My parent got their green card 7 years back, but they live in Kuwait
and come back to US regularly to maintain permanent residency here.
Their green card was solely sponsored by my uncle. Currently my
parents are not in US. If my uncle revokes his sponsorship,
1) what will happen to my parent's green card?
2) Can we get some other person to sponsor their green card? If yes,
what is the procedure?

Further, I got my green card 4 years 11 months back. My green card was
main sponsored by my uncle and co-sponsored by my dad's friend who is
too US citizen. I have already applied US citizenship and just today
completed the naturalization interview successfully, now awaiting oath
letter. If my uncle revokes his sponsorship to my green card, how it
will effect my citizenship process?

Thanks.