As the name suggests, apara karma, actually Punya karma or virtuous deed, of sending one's parents or relatives to moksham is also associated with tears or crying. While Upanishads and Shastras declare the illusiveness of this Universe , we tend to believe that, this body, world, etc.. are true.
Upanishads declare that, like how rivers merge into the ocean, all the names and forms merge into the Brahman, who is Purusha. So, the human being with a specific name, and a form merges into the Supreme in an un-separable manner.
Although we all know this truth, we certainly mourn for the loss of our dear and near. Mind, which is the fort of illusion, or Maya Puri, generates those waves where, the mind enters into an endless state of vibration, which is expressed by one in the form of tears , etc..
Like how our food consists of sweet, bitter, sour dishes etc.., such kind of happenings are all a part of our lives. While men, mourn silently in the hearts, women express their regrets in a much more expressive manner. Music/ songs are an integral part of our culture. Such songs , sung in these special occasions are called as plakkanam, which express the sorrow and grief of the immediate family members.
Immediately after a death or condolence , in a family i is really difficult for the family members to digest the loss of the Sthula SHareeram of the beloved one. Of-course the Sukshma Shareeram, is eternal an attains the punya lokas or merges into the Brahmam depending the Thapas or Yoga performed by that Soul during the life time.
Although enlightned ones never express grief or sorrow of their beloved ones, as they know about the fact - everyone born in this world should depart and every single soul ,which departed from this Universe should be born again.
Still to pacify or appease the Minds of the beloved ones, it's ok to express their emotions by crying etc.. But Shastras say that, after the 10th day, when the Soul is sent to Yama Lokam, one shouldn't be crying - after the period of Ashucham or ritual uncleanliness is over.
After that period and until the Prathama Shrardham (i year anniversary) not even in dream, the deceased appear. As per Puranas, the departed soul travels across various regions to Yama Loka (and will be gives the fruit sof one's karma int hat journey). In that period, the family of the departed ones perform, Nithya Shardam Monthly Shrardam , OOnam (27th day, 45th day and 180th day), and Shroutha Kumbham - giving pot filled with water to appease the thirst of the departed soul.
And of-course once the family of the departed gets used to that fat and comes out of the sorrow, all the members do those services to the departed with the feeling of righteousness.
Although one cries in mind for the loss, dutiful children of the departed ones, feel proud about all the services they did as children to the departed should - both when they were alive and dead. After their physical body is since, children remember the true love, affection showered by one's parent and lives with those memories from then on.
Such is the glory of our Vedic religion.
