A Jewish Funeral is a Jew's Right
Receiving a proper Jewish funeral is so significant and important that many Jews have mandated this in their wills, thereby ensuring that they will be buried in the ways of their ancestors. While one is still alive, one should make it clear to loved ones that his or her funeral must adhere to Jewish tradition.
If one did not leave explicit directions, family or caregivers must ensure that the funeral director will provide the services requeste d (i.e. traditional Tahara — washing and purification of the body, a Shomer — a Jewish person to stay with the deceased until burial, Tachrichim — traditional shrouds, a "kosher" casket, and to be cared for by the Chevra Kaddisha).
Some funeral homes (even those with Jewish sounding names) will not offer these services unless specifically requested (and insisted upon) by the family. That said, responsible funeral directors will go out of their way to accommodate the needs of the family once those needs are made known.
Scheduling the Funeral
It is a Biblical commandment to bury one's deceased immediately after passing, and it is forbidden to leave the deceased unburied overnight unless it is for his honor (i.e. to perform a proper Tahara, obtain shrouds, arrange for a burial plot, gather family, etc.).
One may not put off the burial unnecessarily, for our sages state that the soul is in turmoil until the body is properly buried in the ground. Therefore, there needs to be a great sense of urgency to complete the burial as quickly as possible.
If the passing occurred in the morning, one should try to ensure that the deceased is prepared for burial and buried before dusk of the same day. If this is not possible, the burial should take place on the following day.
If the deceased will be buried in another country, or in other circumstances, consult the Chevra Kaddisha or a competent rabbi for guidance.
Flowers, Music, Viewing
It is not the Jewish custom to send or bring flowers to a funeral or cemetery, for flowers are associated with joyous celebrations. For the same reason, music is not played or sung.
It is also forbidden to hold an "open casket" viewing. This is considered extremely disrespectful to the deceased.
When the Mourner is a Kohen
According to the Torah, a Kohen (descendants of Aaron, the high-priest) is not permitted to come in contact with a deceased b ody. This means that a Kohen cannot be within six feet of where a deceased person may lie; the Kohen may also not be under the same roof as the deceased. For the Kohen, this Biblical prohibition is as serious as the laws forbidding eating unkosher food and violating the Shabbat.
Nevertheless, the Kohen is obligated to attend the funeral of his father, mother, wife (as long as he was permitted to marry her according to Jewish law), son, daughter, brother [including half-brother from his father's side], sister who is not married [including half-sister from the father's side]. In these cases, it becomes a mitzva for him to make himself ritually impure by his attendance.
Forbidden Burial Alternatives
According to Jewish law, a Jew is to be buried as he was born - complete with all his limbs and organs. The human body is considered as sacred in death as it was in life as it contained a G-dly soul. He must be buried in a traditional grave in the ground, so that the body may return to the earth.
Burial in vaults, above-ground mausoleums, crypts, and any other alternatives to a traditional ground burial are strictly forbidden according to Jewish law.
Kabbalah teaches that when a proper kosher burial is not administered, the deceased's soul is stuck in a state of turmoil and cannot find rest until the body's remains are given a proper Jewish burial and allowed to be absorbed into the earth - even after many years!
The Transgression of Cremation
Cremation is explicitly forbidden according to all authentic Jewish opinions and there are never any circumstances where it is permitted. Jewish law considers cremation as pure idol worship, and as "going in the ways of the gentiles." Any instructions to be cremated must be ignored without feelings of guilt or regret.
Aside from the permanent spiritual destruction of the link between the body and soul, if one ever witnessed the action of the "bone-crusher" that is used to pulverize the skeletal remains into the appearance of ashes after the burning of the body, no one of good heart would allow such indignity to come to someone they consider dear.
The prohibition against cremation is so severe that according to Judaism, a person is forbidden to mourn or sit Shiva for one who had himself cremated. This is because in addition to violating Torah law, the person denied G-d's promise of the future Resurrection of the Dead by having his body obliterated.
A proper Jewish burial affects the final peace of the soul and should never be treated lightly. Should a unique situation arise, one must consult a rabbi who specializes in this area of Jewish law for proper guidance.
The Wishes of the Deceased
If the person left specific instructions concerning his funeral and burial, we are morally obligated to do our utmost to carry them out, providing their fulfillment does not violate Jewish law. If one left instructions for actions that go against Jewish law (i.e. to be embalmed or cremated, the donation of organs for science, burial in a mixed-denomination cemetery, burial above-ground, no Tahara purification, the use of a metal casket, etc.), those caring for the deceased are obligated to ignore those wishes without feelings of guilt or regret. Instead one should substitute a proper Jewish burial through the local Chevra Kaddisha.
Most of the time, such requests are made out of ignorance of proper Jewish law and the severity of these matters. Judaism believes that had the person known the eternal consequences of his request, he would not have made them. In addition, now that he is in the "World of Truth," one should not cause him spiritual "pain" by deviating from the ways of the Torah.
Even if the person knew that what he wished went against Jewish law, we can certainly not assist him in committing a sin. On the contrary, we have an obligation to make it right for his soul, so that at least in death, he is laid to rest as a Jew. Our actions will generate merit that will advocate for him in his final judgment before G-d.
In a case where the requests simply deviate from local custom (i.e. the delivery of a eulogy, to be buried next to a spouse, etc.), one should seek the advice of a competent rabbi or the Chevra Kaddisha.