What is the ruling on following the funeral procession of a person who has died and who used to pray to graves for help?

Praise be to Allaah. 

We put this question to Shaykh ‘Abd-Allaah ibn
Jibreen, who replied:

If when he died he was persisting in calling on the
dead for help, it is not permissible to follow his funeral procession. If
nobody discussed this issue with him, we should look to see whether he was
in a land there were any pure monotheists who propagated the message of
Tahweed and if there were any ways in which he could have learned about
Tawheed. It is most likely that proof was established against him, so we
should not follow his funeral procession. Otherwise we may do so. And
Allaah knows best.