Is a Muslim deserving of admonishment if he sneezes and does not praise Allah? Is it better to admonish him or leave him? Has anything been reported regarding this from the Prophet, may Allah’s prayers and peace be upon him?

One who does not praise Allah after sneezing does not deserve to be blessed [with "Yarhamukallah"], rather it is disliked to bless him. It is narrated in the Hadith that the Prophet, peace and blessings be upon him, blessed one who praised Allah and left off one who did not praise Him, saying: "This one praised Allah, but you did not praise Allah." The Prophet, peace and blessings be upon him, guided us, saying: "If one of you sneezes and praises Allah, then bless him. But if he does not praise Allah, then do not bless him." The Sunnah is for the sneezer to say: "Alhamdulillah (All praise is due to Allah)," and for his brother to say to him: "Yarhamukallah (May Allah have mercy on you)," and for the sneezer to reply: "Yahdikumullah wa yuslihu balakum (May Allah guide you and rectify your affairs)."