Rav moshe makes no mention of him being a tzadik, he says he’s the grandson of his beloved friend, he says that he doesn’t give haskamos on dinim(kdarko, this was not unusual) but that from what he saw(emphasis, he says he saw some pieces) definitely didn’t show him the parts i mentioned, or the one ujm mentioned about mixed dancing, which is there on teshuva 37, volume 1..if he showed rav moshe the part where he says women can wear talisim, something rav Moshe says is heresy, do you think he would have had the haskama? Uh, no. Henkin knew what to show to who, and capitalized on his yichus(which all of the haskamos mention). He may have been a grandson, but his father put him in the co ed Yeshiva of Flatbush!
Many times the family of gedolim have more pull and are assumed to be good. It’s usually true, but has pitfalls. Though not nearly as bad as henkin, there’s no way the Torah temimah would have become popular if not for his father and uncle.
Rav waldenburg, rav ovadia, and rav klein all said they have not seen the whole sefer. This was deliberate.
You misrsead rav kleins word of “oso tzadik”, he didn’t say “bnei bonim from the tzadik..” meaning henkin, rather he’s pl making a play on words, “I’ve seen children of children to that tzadik…meaning he saw the grandchildren of rav eliyahu henkin, hertzls grandfather.