Is Nabeel Qureshi a former Muslim?

Recently ITAZ Ahmad made an utterly bizarre effort to undermine the credibility and authenticity of Nabeel Qureshi by asserting Mirza Ghulam Ahmad claimed to be God Almighty. 

In this sense how could Nabeel be a Muslim at all since he wasn't a Unitarian who submitted to God alone?

However a simple fact-check would help one understand Mirza never himself claimed to be God.

While there is no doubt that Nabeel was never part of Orthodox Sunni or Shia Islam. A valid question still remains, was he a genuine Muslim? An adherent of Islam who is now a former Muslim?

Lets define what a Muslim is:

The first thing that one should know and clearly understand about Islam is what the word "Islam" itself means. The Arabic word ''Islam'' means the submission or surrender of one's will to the only true God, known in Arabic as "Allah". One who submits his will to God is termed in Arabic a "Muslim". (source)

And:

"Both "Muslim" and "Islam" come from the same root: "S", "L", "M" (silm) -
meaning; "to submit in peace"; "surrender in obedience"; and this immediately implies a relationship between two entities, one being superior to the other or in charge of matters." (source)

This is the exact same chain of reasoning Muslims utilize to argue Adam, Noah, Abraham, Moses, David and Jesus were "Muslims". They are Muslims in the sense that they surrendered their will to God.