Neil Lamb treated Oliver Queen at Starling General Hospital when he returned to Starling City after being rescued from Lian Yu. Neil revealed to Moira Queen the extent of Oliver's injuries and current emotional state as they watched him through an observation window. Neil warned Moira that her son might have become a completely different person and suggested to brace herself for any major changes she saw in Oliver.
After Moira was almost shot and suffered a concussion, Neil treated her at Starling Hospital. He assured Oliver and Thea Queen that Moira would be alright and could go home as long as someone watched over her.
Years later, after Thea began suffering the fatal effects of her bloodlust, Neil allowed Oliver to take her from Starling General.