Believing Muhammad (s.a.w.) is hazir-nazir.
Q. If someone believes that Muhammad (s.a.w.) is hazir-nazir (present and can see all in the world at all times) then has he lost his Imaan? Would he remain a Muslim?
A. If someone has this belief, then it would not be said that he has lost his Imaan, instead, it would be said that he has committed an act of shirk.
As such, it is compulsory upon him to stop having such a belief, re-affirm his faith in Allah and make sincere repentance for what he has done.
And Allah knows best.
Mufti Waseem Khan