In Congress, there are two different branches; Senate and House of Representatives. The Senate helps with making Laws, and the House of Representatives passes those laws before it becomes official.
Here are the requirements -
Senate: 30yr, Citizen of US for 9 years, must be inabitants of US
House Of Rep. : 25yr, Citizen of US for 7 years, inabitant of US
THEREFORE he can be apart of the House of Representatives at his state now... If he waits one more year of citizenship and three more years of life until he is 30 THEN he can be Senate.
