Can a person apply for a green card in his home country after marrying US citizen spouse?

Generally, a foreign national who entered the U.S. lawfully and with inspection, such as with a B1/B2 visa, and who then becomes married to a U.S. citizen, may apply in the United States to adjust status to become a Lawful Permanent Resident (to get a "Green Card") regardless of whether his visitor's visa may have expired. Alternatively, however, the foreign national spouse may travel abroad and apply for "consular processing," but that could become problematic, especially if the foreign national may have become subject to a 3-year bar to re-entering if he/she remained unlawfully present in the U.S. for 180 days or longer (or a 10-year bar if unlawfully present for a year or longer). It would be wise to work with an immigration attorney who, after learning all of the relevant information about you, your immigration-related history, your spouse, etc., would be able to advise you about eligibilities, options and strategies and represent you in the application process.

Yes, but this person also can get a green card in the US without leaving.