Patents - under a year. Brother/sister - depends on the country but at least 12 years and as I said it can be more depending on the country.
This is not legal advice and a client attorney relationship is not created. For a free consultation call (718)234-5588.
Parents could take 6-10 months, depending on how smoothly everything goes (especially at the embassy stage). Brothers and sisters are in the last preference category and take a very long time (10-12 years).
The statement above does not create an attorney-client relationship. It is intended as general information only and it is not a substitute for legal advice. You should consult with a licensed attorney to discuss the specific facts and circumstances of your case.
Parents of U.S. citizens are considered "immediate relatives" and visas are available. Processing times take about 6-8 months. Siblings of U.S. citizens must wait for a visa number to become available. The wait can exceed 12 years, depending on what country they are from.
You should consult with an attorney to discuss an appropriate plan (perhaps plan for the parent to file for your brothers or sisters after they immigrate to the U.S., although usually it is advisable for you to do the I-130 as well, in case your parent decides not to immigrate, abandons residence, passes away or something else happens. )
This general information does not establish any attorney-client relationship. There may well be factors not mentioned in the question which could and should be addressed in an attorney consultation.