Should we abandon our friend who became a Shiite?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

You should not forsake your friend in this case. If you did this you would be assisting Satan and wrongdoers against him.  You should be lenient with him, advise him, remind him of his bad deed and explain to him the corruption and danger of Shee’ah beliefs. You may also use the books of Ahlus-Sunnah in this regard. Continue to do this and perhaps Allaah will guide him at your hands.

You should only forsake him if you fear that sitting and dealing with him might affect your religion and morals, or if deserting him will deter him from this wrongdoing. 

Allaah Knows best.