In Megilla Rashi names 48 nevi'im who were misnaveh ledoros, one of them is Boruch and another one is Nerya his father. Nerya never said anything in Tanach! I understand that any novi that is called by his father's name it means his father was also a novi but if this is enough to consider him a novi then there are many more on the list that are called the son of their father and their father is not on the list.
Ovaid
(a) Rashi's source appears to be the Beraisa on 14b which explicitly lists Neriyah as one of the eight Nevi'im who descended from Rachav and Yehoshua. The Beraisa also lists Mechasyah, Seraya's father, which is why Rashi counts Mechasyah in his list of 48 Nevi'im even though no Nevu'ah of his was recorded in Tanach.
(b) However this leads us to a stronger question. Why didn't Rashi count the other Nevi'im mentioned in that Beraisa, such as the fathers of Yirmeyah and Shalum. An even stronger question is why Rashi didn't mention Chanamel, who is also recorded in the abovementioned Beraisa as a Navi (and not just the father of a Navi)!
Indeed, we may also ask how the Beraisa itself knew that Neriyah and Mechasyah were Nevi'im. Apparently it was deduced from the fact that their names are mentioned along with their children, as you pointed out. But if so your question remains, why didn't Rashi count the fathers of all of the other Nevi'im in the list of the 48?
These questions are asked by Maharsha (14b) and Yaavetz (14a, in Neharde'a edition of the Shas) among others.
(c) The Mitzpeh Eisan answers that the fathers of the other Nevi'im were indeed Nevi'im, but their Nevu'ah was not recorded in Tanach because it was not needed for future generations (as the Gemara here explains). The 48 who are listed were those whose prophecies were written for future generations.
We can use the same answer for Chanamel; his prophecy was not written in Tanach because it was not needed for future generations. That is why he is not among the 48 listed in Rashi.
(d) What remains to be explained is why Baruch and his father and Sarayah and his father were included in the list of 48 Nevi'im if their prophecies were not recorded, and presumably were not needed for future generations?
I would like to suggest the following answer. Since we find in Tanach that Baruch and Sarayah were students of Yirmeyah, a prophet whose words were indeed recorded for future generations, we can assume that their prophecy revolved around the words of their master. (Their prophecies were not recorded individually because their words were the words of their master, not because their words were not needed for future generations.) Since their prophecies had eternal meaning they were included in the list of 48 just as their master was included in the list.
As for their parents, since they were mentioned together with their children it may be assumed that they were the same type of prophet as their children, i.e. students of Yirmeyah who prophesized involving the words of Yirmeyah. If their sons were included in the list of 48 then they ought to be included for the same reason.
I hope this helps make things clearer.
Best wishes,
Mordecai Kornfeld
Kollel Iyun Hadaf