He has a clean heart but he does not respect his parents

if a person prayers, and dose various other muslims deeds and has a clean heart yet fails to respect their parents or even care for their parents is this wrong? and will they be punished for it? 

Praise be to Allaah. 

Yes, that is counted as a sin for which a person will be punished, because Allaah says (interpretation of the meaning):

“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” [al-Israa’ 17:23-24]

 Shaykh Sa’d al-Humayd

Every kind of annoying one's parents, whether in word or deed, is an act of disobedience which means that the child is a sinner, because it goes against the command and prohibition of Allaah, Who has commanded us to speak to them kindly and treat them kindly. Allaah says (interpretation of the meaning):

“but address them in terms of honour.

And lower unto them the wing of submission and humility through mercy”  [al-Israa’ 17:24]

 It is forbidden to dishonour them by saying or doing bad things to them. Allaah says (interpretation of the meaning):

“say not to them a word of disrespect, nor shout at them” [al-Israa’ 17:23]

 If the child does that, then he has to repent to Allaah and seek his parents’ forgiveness, so that he may escape the punishment.