Śrī Caitanya Mahāprabhu caused the dead son to speak about knowledge, and then the two brothers personally became the sons of Śrīvāsa Ṭhākura.
This incident is described as follows by Śrīla Bhaktivinoda Ṭhākura in his Amṛta-pravāha-bhāṣya. One night while Śrī Caitanya Mahāprabhu was dancing with His devotees at the house of Śrīvāsa Ṭhākura, one of Śrīvāsa Ṭhākura’s sons, who was suffering from some disease, died. Śrīvāsa Ṭhākura was so patient, however, that he did not allow anyone to express sorrow by crying, for he did not want the kīrtana going on at his house to be disturbed. Thus kīrtana continued without a sound of lamentation. But when the kīrtana was over, Caitanya Mahāprabhu, who could understand the incident, declared, “There must have been some calamity in this house.” When He was then informed about the death of Śrīvāsa Ṭhākura’s son, He expressed His regret, saying, “Why was this news not given to Me before?” He went to the place where the son was lying dead and asked him, “My dear boy, why are you leaving the house of Śrīvāsa Ṭhākura?” The dead son immediately replied, “I was living in this house as long as I was destined to live here. Now that the time is over, I am going elsewhere, according to Your direction. I am Your eternal servant, a dependent living being. I must act only according to Your desire. Beyond Your desire, I cannot do anything. I have no such power.” Hearing these words of the dead son, all the members of Śrīvāsa Ṭhākura’s family received transcendental knowledge. Thus there was no cause for lamentation. This transcendental knowledge is described in the Bhagavad-gītā (2.13): tathā dehāntara-prāptir dhīras tatra na muhyati. When someone dies, he accepts another body; therefore sober persons do not lament. After the discourse between the dead boy and Śrī Caitanya Mahāprabhu, funeral ceremonies were performed, and Lord Caitanya assured Śrīvāsa Ṭhākura, “You have lost one son, but Nityānanda Prabhu and I are your eternal sons. We shall never be able to give up your company.” This is an instance of a transcendental relationship with Kṛṣṇa. We have eternal transcendental relationships with Kṛṣṇa as His servants, friends, fathers, sons or conjugal lovers. When the same relationships are pervertedly reflected in this material world, we have relationships as the sons, fathers, friends, lovers, masters or servants of others, but all these relationships are subject to termination within a definite period. If we revive our relationship with Kṛṣṇa, however, by the grace of Śrī Caitanya Mahāprabhu our eternal relationship will never break to cause our lamentation.
Ref >> Srila Prabhupada Vani.