Short answers, pulled from the story.
The Volga River valley turned to dust in the spring of 1921 due to a severe drought combined with three-and-a-half years of World War I and the Russian Civil War. Bolshevik war communism policies like prodrazvyorstka forced peasants to surrender grain for little or no payment, leading farmers to drastically reduce crop production.
An official Soviet publication from the early 1920s concluded that about five million deaths occurred in 1921 from famine and related disease. More conservative figures counted not more than one million fatalities while other assessments based on American Relief Administration data spoke of two million dead.
Herbert Hoover responded immediately by appointing Colonel William N. Haskell to direct operations in Russia through the American Relief Administration. The ARA distributed food aid throughout Europe since 1914 and fed over 10 million people each day within a year of emergency feeding beginning in 1921.
Lenin decreed the New Economic Policy on the 15th of March 1921 after being convinced by multiple factors including the Kronstadt rebellion and large-scale peasant uprisings like the Tambov Rebellion. This policy reversal allowed foreign aid organizations to bring relief to Russia following earlier refusals due to railway control demands.
The Bolsheviks launched a campaign to seize church property starting in 1922 when authorities confiscated over 4.5 million golden roubles worth of religious assets. One million gold roubles were spent specifically for famine relief efforts according to official records while a secret letter from the 19th of March 1922 revealed Lenin's intention to seize several hundred million golden roubles.