It is not valid to bid farewell to a deceased person and ask to convey the salam to someone who died before him
Machine translationRead the Arabic original
Question:
May Allah reward you with good and do you well. You are also asking this question: Is it permissible for me, if one of my relatives dies and I am bidding him farewell, to say, “Convey my salam so-and-so or so-and-so,” when he is dead? Is this permissible?
Answer:
There is no evidence for this, that one who is near death should be instructed to convey the salam to so-and-so or so-and-so among the dead. However, what is prescribed is to make du'a for the dead, seek forgiveness for them, and visit their graves in the prescribed manner: visiting them, conveying the salam to them as one does to the living, making du'a for them, and seeking forgiveness for them. This is what has been reported. Yes.
May Allah reward you with good and do you well. You are also asking this question: Is it permissible for me, if one of my relatives dies and I am bidding him farewell, to say, “Convey my salam so-and-so or so-and-so,” when he is dead? Is this permissible?
Answer:
There is no evidence for this, that one who is near death should be instructed to convey the salam to so-and-so or so-and-so among the dead. However, what is prescribed is to make du'a for the dead, seek forgiveness for them, and visit their graves in the prescribed manner: visiting them, conveying the salam to them as one does to the living, making du'a for them, and seeking forgiveness for them. This is what has been reported. Yes.
Source
قناة «العلامة الدكتور صالح الفوزان»، 4245- لا يصح توديع من مات وطلب إبلاغه السلام لمن مات قبله - الشيخ صالح الفوزان — youtube.com
The Arabic text is a machine transcription of the audio recording.