Gil Kane goes solo on The Hawk and the Dove 5 (April/May 1969).
The story in this issue is a good one, but also highlights the difficulty with this series. At the top of the tale Judge Hall has to deal with a man accused of robbery, who had saved the judge's life many years before. Judge Hall is certain that the man is telling the truth when he says he was framed, and discusses the case with his sons.
This prompts Hank and Don to go into action as Hawk and Dove, and find the real guilty party. It turns out that two of the witnesses who identified the guy are part of a stolen car ring.
As Hawk pursues them, one of the bad guys drops a crate on him. Dove takes him to the hospital, after he changes back to Hank, but is determined to find who has injured his brother.
When Dove discovers that the guy who had saved his dad really is the guilty party, as well as being the one to injure Hank, he loses it completely. He gets just as violent as Hawk as he beats the man up before taking him in.
Later, Don is overcome with remorse for his actions. Hank is impressed that his brother finally fought, but also gives him some kind words, about how it's ok that he lost his cool the one time, it doesn't mean anything. Still, issue by issue it's Don that is changing, becoming more like Hank, who is not really changing at all. Ideally they should both be moving to the other ones point of view.
Despite the fact that the story says "the end," there are actually a few more panels to it, a very quick lead in to the next issue of Teen Titans. As Hawk and Dove pursue a villain, they wind up running into Robin, Kid Flash, Speedy and Wonder Girl.