Filtering navigation with pre_get_posts

I am trying to create a plugin to create a custom post type to track a user’s progress through a ten week program we offer. I have defined a custom post type (to simplify things here we’ll call it “week”) and created a post for each of the ten weeks. If a user is on week 3, I want to filter the week posts so that they are unable to view weeks beyond their current point.

I accomplished this by using “pre_get_posts” as listed below. This works as I would expect, however it does not seem to impact the calls to next_post_link. For example, when viewing week 3 during week 3, a link still appears for week 4 (although it is a dead link).

What is the proper way to impact a query so next_post_link does not emit a link on the last filtered post?

Code so far:

function xyz_pre_get_posts($query) {
    global $currentWeek;
    if ($query->is_main_query() && !is_admin() && is_single() && 'week' == $query->query_vars['post_type']) {
        $meta_query = array(
            array(
                'key' => 'week',
                'value' => $currentWeek,
                'compare' => '<='
            )
        );
        $query->set( 'meta_query', $meta_query );
    }
}
add_action('pre_get_posts', 'xyz_pre_get_posts');