Buy FXAIX by Feb 12, 2086.

My son just turned a year old. I’ve been investing in FXAIX for him for the last 8 months. The goal is to ensure he is a multi millionaire by the time he’s eligible to retire later in life. Is there something better I should be doing for him ? I know they say starting early is the best thing to do. If I’m doing something wrong, trying to catch it early. Any help/input would be greatly appreciated !