The mother of Siranudh “Psi” Scott, the 29-year-old scion whose childhood abuse accusations against his brother triggered public sympathy and revealed a rupture inside one of Thailand’s richest families, on Friday dropped her “ungrateful child’’ lawsuit against her younger son as she appealed for space to “heal’’ her family.Chiranuj Bhirombhakdi filed a lawsuit in February against Psi under a 1908 law that enforces filial duty, in a country where family ties border on the sacrosanct.Psi, a...