After the revivals of Sub-Mariner, Captain America, The Human Torch and even after a manner The Vision, Red Raven, Toro, and some other characters from the Golden Age, we finally discover what became of two veterans of the All-Winners Squad - The Whizzer and Miss America. The answer came of all places in the debut issue of Giant-Size Avengers by Roy Thomas and Rich Buckler (drawing in his full-on Kirby clone mode).
It turns out that after the war, Whizzer and Miss America were wed. At this time it had not been established that Whizzer had met Cap before the end of the war and so the story is written as if he was only familiar with the replacement Cap who had appeared in issues of Captain America and The Falcon. But the Bob Frank of the 70's is a much more desperate soul than we remember from his Golden Age heyday. His wife Madelyn has long been gone, dying in childbirth as she delivered twins. For a time those twins were thought to be Wanda and Pietro, but of course later we learn differently.
The Whizzer wants Cap and the Avengers to help him rescue his son but things get complicated when Nuklo divides into three entities which all need to be rounded up. Before he can become the zero point for a devastating nuclear blast his "sister" the Scarlet Witch hits him with a hex which causes him to expell his radiation relatively harmlessly. He is then put once again into the care of the United States military.
Robert Frank suffers a heart attack during these events and while he is recovering watches his "son"Pietro marry Crystal of the Inhumans. Then apparently Bob Frank disappears again.
When next we meet him he is again desperate for aid but before he can summon it he falls victim to the Living Laser who uses his powers to delude the aged speedster into thinking he is being attacked by old foes ISBISA, Future Man and Madame Death. He fights the Avengers while under this influence until things are put right eventually.
The story extends over into the 1976 annual where we learn that the military plan to use Nuklo as a weapon under the command of a corrupt general who is working in league with the Living Laser, who himself covets and for a time possesses the Serpent Crown.
It is a convoluted story which also features subplots about the crown itself and a recently revived Wonder Man, but during the course of the tale Nuklo is once more brought to heel and his threat ended when Whizzer himself casts himself into his son at the moment of critical mass, again allowing the energy to dissipate with limited harm. But both are severely weakened. The Whizzer goes on to hang around the Avengers Mansion for a short time before he again disappears.
Nuklo is sent to Project Pegasus where he is cared for, but where he comes into conflict with The Thing and Quasar. After this he is sent to a hospital setting where he can be taught and for a time makes great gains in his maturation process.
All of that is put into jeopardy when Bob Frank once again shows up on the doorstep of his presumed daughter the Scarlet Witch, at a time when she and her husband The Vision are away from the Avengers team. Wanda now knows that Frank is not her father, rather that his own children were stillborn and in his grief at the death of his wife he didn't realize. Once again at this point Wanda and Pietro are uncertain who their father is, though they know their mother was a woman named Magda.
All this takes place in the second issue of the limited series Vision and the Scarlet Witch, which in four issues by Bill Mantlo and a young Rick Leonardi makes monumental changes to the status quo of the Marvel Universe. By the fourth issue of this series the twins will learn for the first time that Magneto is in fact their father.
Also revealed in the Whizzer story is that ISBISA was in fact responsible for the "accident" which irradiated the couple decades before resulting in the mutation of Nuklo and the death of their other children. He continues to take his vengeance by keeping tabs on Nuklo as the lead scientist now in charge of his care. His ultimate goal is to harvest the massive amounts of radiation Nuklo is able to generate and make use of it to pursue his criminal plans.
In a terrific struggle in which the Vision is seriously wounded, Robert Frank lays down his own fragile life to save his son one more time, hoping to the end to redeem his years of abandonment. It's a dour and tragic close to a life which in its glory was filled however briefly with high spirits, courage, romance, and true heroism.