wp_query not searching with apostrophe

Try using sanitize_text_field instead of esc_html

wp> $search_query = "Dalton's Law <br/>";
string(18) "Dalton's Law <br/>"
wp> $query = apply_filters( 'get_search_query', $search_query );
string(18) "Dalton's Law <br/>"
wp> $esc_html = esc_html( $query );
string(29) "Dalton&#039;s Law &lt;br/&gt;"
wp> $sanitized = sanitize_text_field( $query );
string(12) "Dalton's Law"

esc_html should be used to escape output before it goes into HTML.