i think it is impossible to summon people who have died

Absolutely Yes.

There is NO consciousness after death... (Ecclesiastes 9:5-6) For the living are conscious that they will die; but as for the dead, they are conscious of nothing at all, neither do they anymore have wages, because the remembrance of them has been forgotten. 6 Also, their love and their hate and their jealousy have already perished, and they have no portion anymore to time indefinite in anything that has to be done under the sun. Caution; Demons CAN be summonsed...by the use of Tarot cards, and seances. the Bible warns against this. (Deuteronomy 18:10-12) There should not be found in you anyone who makes his son or his daughter pass through the fire, anyone who employs divination, a practicer of magic or anyone who looks for omens or a sorcerer, 11 or one who binds others with a spell or anyone who consults a spirit medium or a professional foreteller of events or anyone who inquires of the dead. 12 For everybody doing these things is something detestable to Jehovah, and on account of these detestable things Jehovah your God is driving them away from before you.

nope... chances are that they summon you as chacelours but have spelled your summons incorrectly.

There is no such word as "chacelours". What did you mean to spell?

No. Once dead, people cease to exist... And so can do nothing... (Ecclesiastes 9:5-6) For the living are conscious that they will die; but as for the dead, they are conscious of nothing at all, neither do they anymore have wages, because the remembrance of them has been forgotten. 6 Also, their love and their hate and their jealousy have already perished, and they have no portion anymore to time indefinite in anything that has to be done under the sun. However, Demons can be summoned...invited into our lives...this we should NOT do. (Leviticus 19:31) “‘Do not turn yourselves to the spirit mediums, and do not consult professional foretellers of events, so as to become unclean by them. I am Jehovah YOUR God. (Deuteronomy 18:10-12) There should not be found in you anyone who makes his son or his daughter pass through the fire, anyone who employs divination, a practicer of magic or anyone who looks for omens or a sorcerer, 11 or one who binds others with a spell or anyone who consults a spirit medium or a professional foreteller of events or anyone who inquires of the dead. 12 For everybody doing these things is something detestable to Jehovah, and on account of these detestable things Jehovah your God is driving them away from before you. (Galatians 5:19-21) Now the works of the flesh are manifest, and they are fornication, uncleanness, loose conduct, 20 idolatry, practice of spiritism, enmities, strife, jealousy, fits of anger, contentions, divisions, sects, 21 envies, drunken bouts, revelries, and things like these. As to these things I am forewarning YOU, the same way as I did forewarn YOU, that those who practice such things will not inherit God’s kingdom.

Yes they can hear you even if you do not talk out loud. They are standing right next to you. Its not like they are someplace else.

Nope. The dead are no more. +5

Again it is complicated. I happened to read some real experiences of the people. Again posing anotehr question science is still trying to figure out. Death can be defined? not yet.