Simplify the following text for a Grade 10 native English-speaking person.
Original: He currently holds the advisory post of Minister Mentor , created by his son , Lee Hsien Loong , when the latter became the nation 's third prime minister in August 2004 .
Simplified: He is currently Minister Mentor , a post created when his son Lee Hsien Loong became the nation 's third prime minister on 12 August 2004 .