First of all, Nabeel was part of an Islamic sect called Ahmadiyya, which is rejected by most of Islam. They don't believe that Muhammad was the last prophet and disregard fundamental teachings of the Qur'an. Ahmahis are to Islam what the Jehova's Witnesses are to Christians. They consider themselves to be part of the religion, but they deny parts of the doctrine.
Secondly, if Nabeel lost his family, then why are his parents caring for him, visiting and helping him now when he's battling cancer? Just a few months ago he made a video with his father in which he explains that his father completely accepts his conversion to Christianity and they agree to love each other in spite of their beliefs. If you watch his vlogs, you will find out that he never lost the support of his family after his conversion, and many of his Muslim friends send him emails of encouragement and good wishes.
(video removed - if you want to watch Nabeel's videos, look up on YouTube "NQMinistries" because I'm not allowed to post videos despite the fact that they are relevant to the discussion).