Maintain the ties of kinship
The Messenger of Allah (sal Allahu alaihi wa sallam) said: “He who believes in Allah and the Last Day, let him be hospitable to his guest; and he who believes in Allah and the Last Day, let him maintain the ties of kinship; and he who believes in Allah and the Last Day, must speak good or remain silent.”
[Sahih Al-Bukhari and Muslim]
Once again this Hadith highlights the importance of maintaining the ties of kinship, therefore a Muslim should always be kind to his relatives, especially his parents.
A Muslim enjoins considerate treatment to all relatives and should maintain a relationship with them at all costs, so much so that even if they misbehave and sever relations with him, he should make efforts to restore not only the relationship with them but also their rights. This is what kindness to relatives really means.
Islam has laid great stress on these issues due to the importance of maintaining a harmonious society starting first and foremost within the family unit which includes both paternal and maternal relatives.
And Allah knows best!