My family is literally driving me crazy!?

I am very very close to both of my parents. They have been married for almost 20 years....I dont know what id do without either one of them in my life. But anyways...im so tired of feeling sorry for both of them...and wanting to help both of them and not being able to. They have everything they want and need in life....big beautiful house, 3 grown kids, multiple cars, motrocycle, you name it....I guess I dont understand why they act like their so unhappy all the time. The way I see it, you should be grateful for what you have..be grateful your alive....but their totally not. Dad mopes around and complains ALL day...gripes at everyone. Mom mopes around....I always hear them say they hate their lives...and here I am thinkin wtf..how can you say you hate your life? Its upsetting. The other day my dad told me that he so tired of sleeping so much, or not doing anything..that he thinks he'd just rather be dead sometimes...I started crying....and he didnt understand why i was so emotional. Like I said..im very close with the both of them...but their driving me nuts. They both work good jobs..and come home..complain....my mom cries for no reason.....and yes maybe it is in their relationship..BUT...theres more to it. Im so sick of trying to please the both of them...I sit here sometimes..and im like...why dont you and mom go do something together? they both sit around...and its like if they have 1 or 2 things to do for the day...their whole day is full.....I know I said alot but it still doesnt explain truly what I mean. Im just ready to go nuts..I want everyone to be happy....i have my own probs to deal with!