This letter is from ' Abdul ' Aziz Bin 'Abdullah Ibn Baz to the honorable brother Mr. Sh. A. G. may Allah protect him.
A ssalamu 'alaykum warahmatullah wabarakatuh (May Allah's Peace, Mercy, and Blessings be upon you!)
In regard to your Fatwa request registered in the Department of Scholarly Research and Ifta' under no. 1841 on 1/5/1408 in which you ask many questions, I would like to inform you that it is not permissible to initiate greetings with nonMuslims. On the other hand, it is Sunnah (action following the example of the Prophet) to greet Muslims, even if they are known to commit sins but you can advise them, command them to do good and forbid them from evil. If, however, they insist on their sins and reject your advice, you can stop initiating greetings with them and returning their greetings. Moreover, the Permanent Committee for Scholarly Research and Ifta' has previously issued Fatwas (legal opinions issued by a qualified Muslim scholar) in this regard and the copies are attached to this letter. You will find them beneficial, in sha'aAllah (if Allah wills).
May Allah guide us all to what pleases Him! Peace be upon you!