Re: Do you Owe your parents....
This practise was encouraged by the Prophet SAW :)
A man came to the Prophet and asked; “Oh! Messenger of Allah, now that my parents are dead, is there any act of dutifulness left for me to do towards them?”
The Prophet answered; “Yes. There are four things; Supplication for them, praying that they are forgiven, fulfilment of their wills, being kind to their friends and maintaining good relations with those of your relatives with whom your kinship is established only through them.” (Related by Abu Dawood, Ibn Majah and others).
Also, I remember a hadith where Hazrat Aisha r.a mentioned how she was envious of Hazrat Khadeeja r.a. bcoz te Prophet SAW would still send presents to Hazrat Khadeeja's friends years and years after her dealth.
So it seems that we are encourage to keep ties of some form with the ppl our parents had ties with... doing favours is one such way.