Yes, the deceased hear the greetings of peace when we pray for them, and they receive the supplications we send them. This is based on the Prophet’s (pbuh) hadith, (The Messenger of Allah admonished the inhabitants of the well at Badr: “O Abu Jahl bin Hisham! O Utbah bin Rabi`ah! O Shaybah bin Rabi’ah (and he called their leaders by name)! Have you found what your Lord promised to be true (the Fire)! I certainly found what my Lord has promised me to be true (victory).” Umar said, “O Allah’s Messenger! Do you address a people who have become rotten carrion!” He said, “By He in Whose Hand is my soul! You do not hear what I am saying better than they do, but they cannot reply.”)
نعم الميت يسمع السلام حينما نسلم عليه و يصله الدعاء إذا دعونا له، لحديث الرسول صلى الله عليه عندما مر علي موتي صناديد قريش بعد غزوة بدر، وقف ينادي : ( يافلان بن فلان إني وجدت ما وعدني ربي حقا فهل وجدتم ما وعدكم ربكم حقا) قال عمر ابن الخطاب : يارسول الله انك تنادي أجسادا لا ارواح فيها، فقال الرسول عليه الصلاة والسلام : ( ما أنتم بمسمع لما أقول منهم لكن لا يستطيعون أن يجيبوا).