Technically, the answer would have to be "it's not known", since there just doesn't appear to be enough in-universe information to say for sure.
However, we might have enough to go on to say that it's likely that Yancy Sr. is able to emit delta waves, and therefore doesn't possess the same superior-yet-inferior trait his son does. (Spoilers follow...)
In the episode "The Day the Earth Stood Stupid", Nibbler says:
There is but one being who can resist them. A child of destiny whose bizarre brain wave pattern makes him immune to the Brain Spawn attack. He is the hope of the universe. The fate of your world, perhaps all worlds, rests in his special mind.
In the later episode "The Why of Fry", these are some of the statements made by various characters (emphasis mine):
Ken: Enough! Fry, it is my duty to inform you that the fate of humanity, the fate of our race, indeed the fate of all that exists and ever will exist rests with you. You are the single most important person in the universe.
Ken: Oh, my. Anyway, your immunity is due to the fact that you lack the delta brainwave. It's a genetic abnormality which resulted when you went back in time and performed certain actions which made you your own grandfather.
Big Brain: It appears we are in the presence of the fabled one.
Nibbler: We had no choice. You were the only one who could help us. What is one life weighed against the entire universe?
Nibbler: Please. Our saviours foresee that in a thousand years, for one moment, the fate of the universe will depend on you. Since you will not live that long I must freeze you now.
The first takeaway is that Fry's ability is due to a specific "genetic abnormality", and it's quite clear that Fry and Yancy Sr. are genetically distinct from one another. While being one's own grandfather appears to be a cause of the abnormality, it may just be a necessary, but not sufficient, factor in causing an individual to lack delta brain waves. Other genetic factors unique to Fry, but not possessed by Yancy Sr., may contribute.
Fry is also repeatedly referred to as the only one able to help fight the Brain Spawn. It's possible that he's simply the only one in the right place and at the right time to help, or that he's the only one the Nibblonians are aware of. But it could also mean he's the only one period that exhibits a lack of delta waves, meaning Yancy Sr. does exhibit them.