Tā zhège hútuchóng, lián zìjǐ de shēngrì dōu wàngle.
That bungler even forgot his own birthday.
Tips
memory
糊涂 ('muddleheaded') + 虫 ('worm/bug') — calling someone a 'muddle-bug'. The 虫 suffix is a common informal way to label a habitual type of person: 懒虫 (lazybones), 跟屁虫 (hanger-on), 网虫 (internet addict). It's affectionate-teasing rather than harsh.
