Sonny and Tobias never had a father/son relationship. Tobias' parents felt that it would be a good P.R. move to have their twenty-year-old son adopt a twelve-year-old Romanian orphan, Alexandru Lupei, to show that Irresponsible, Partying Tobias was now Responsible Single Dad Tobias.
Tobias was far more corrupting big brother than father to Alexandru, whom he nicknamed Sonny. Sonny was in love with Tobias from their first meeting, and Tobias was aware of the power he had over the boy. However, nothing sexual ever occurred between the pair until after Sonny turned eighteen.
In Carnal Invasion XI, it is revealed that Muel feels that it's time for Tobias to ask Mistress Kali to resurrect his body, which had been crushed to a fine powder with the intent of sprinkling it through space so it would be close to impossible for it to be repaired. With the pair sharing Muel's head space, it is clear to Muel that Tobias has changed his ways and will spend his days making others' lives better rather than worse in the future.
Tobias is unsure about returning to his physical form. He thinks he might be able to be more effective by moving from host to host as needed. Besides, Tobias is worried that his one true love may continue to reject him, and this is a possibility that Tobias isn't sure that he can face.