As Muslims, we all believe in our parents’ rights upon us and our obligations to be good to them, obey them and to treat and deal them in the best way as possible. It is not just because they are the cause for our existence. It is also not because they did a great deal of good to us that we must repay and respond to in a proper manner. But it is first and foremost because our Lord, Almighty Allah has made it an obligation upon us to obey them and treat them in a well manner. No doubt, Allah mentions their rights in conjunction with His own right of being worshiped alone without any partner and co-equal. Allah the Exalted has said:
“And your Lord has decreed that you worship none but Him. And that you be dutiful to your parents. If one of them or both of them attain old age in your life, say not to them a word of disrespect, nor shout at them but address them in terms of honour. And lower unto them the wing of submission and humility through mercy, and say: “My Lord! Bestow on them Your Mercy as they did bring me up when I was small.” (Al-Isra 17:23, 24)
And He (SWT) also said:
“And We have enjoined on man (to be dutiful and good) to his parents. His mother bore him in weakness and hardship upon weakness and hardship, and his weaning is in two years give thanks to Me and to your parents, unto Me is the final destination.” (Luqman 31:14)

Source:
http://pathway2jannah..com/2015/01/parents-their-rights-and-our-behaviors.html

Nice post! What's the best way to treat a parent that left you and your siblings at an age when you all are not fully matured, leaving you all heartbroken?