It means "...that means a lot to me".
If it's a question, it means, "What mean everything to my dad?" If it's a sentence fragment, it could mean, "...that mean everything to my dad."
Many kisses for you my love.
"You are everything to me" in Spanish is "Eres todo (or "toda" if you are speaking to a female) a mí". It is pronounced "AIR-ace TOE-doe ah me". Please see this site for confirmation of the translation: http://www.answers.com/library/Translations
ustedes significan todo para mi ustedes son mi mundo
I have waited a long time for this
You study a lot for your favorite class.
Literally translates to: "I have a lot of love for you, always."
They study a lot for science class.
It helped me a lot because now I'm in the best math group.
helped a lot because now I'm in better group for mathematics
te quiero mucho
for