Ravana was killed by Lord Ramacandra and was destined for hellish life, but by Lord Ramacandra's advice, Vibhisana, Ravana's brother, performed all the duties prescribed in relation to the dead. Thus He was kind to Ravana even after Ravana's death

Expressions researched:
"Rāvaṇa was killed by Lord Rāmacandra and was destined for hellish life, but by Lord Rāmacandra's advice, Vibhīṣaṇa, Rāvaṇa's brother, performed all the duties prescribed in relation to the dead"

Srimad-Bhagavatam

SB Canto 9

To save a diseased person from ghostly life, the funeral ceremony, or śrāddha ceremony, as prescribed in authorized śāstra, must be performed. Rāvaṇa was killed by Lord Rāmacandra and was destined for hellish life, but by Lord Rāmacandra's advice, Vibhīṣaṇa, Rāvaṇa's brother, performed all the duties prescribed in relation to the dead. Thus Lord Rāmacandra was kind to Rāvaṇa even after Rāvaṇa's death.

SB 9.10.29, Translation and Purport

Śrī Śukadeva Gosvāmī said: Vibhīṣaṇa, the pious brother of Rāvaṇa and devotee of Lord Rāmacandra, received approval from Lord Rāmacandra, the King of Kosala. Then he performed the prescribed funeral ceremonies for his family members to save them from the path to hell.

After giving up the body, one is transferred to another body, but sometimes, if one is too sinful, he is checked from transmigrating to another body, and thus he becomes a ghost. To save a deceased person from ghostly life, the funeral ceremony, or śrāddha ceremony, as prescribed in authorized śāstra, must be performed. Rāvaṇa was killed by Lord Rāmacandra and was destined for hellish life, but by Lord Rāmacandra's advice, Vibhīṣaṇa, Rāvaṇa's brother, performed all the duties prescribed in relation to the dead. Thus Lord Rāmacandra was kind to Rāvaṇa even after Rāvaṇa's death.