He could theoretically push the gold brick away from himself, and due to Newton's 3rd law (Every action has an equal and opposite reaction), the same amount of force would recoil back at him from the gold brick. As a result, he will move in the opposite direction from the gold brick, and since it as an ideal frozen lake (meaning there is no friction present), he will keep going until he reaches the edge of the lake.
And I don't know if he's still a fool. That's up to you.
