The Younger son was a seal master and master at medical ninjutsu

[JDuzumaki92]

There is no evidence of his or the elder son's abilities once so ever, other than obito's explanation to naruto; however, if we are only looking at the descendents, in this case, the Senju Clan and the Uzumaki clan, one can guess that he had to of been a seal master due to the Uzumaki's renown for being seal masters and maybe he was a master or even the creator of medical ninjutsu. What do you guys think?

 

[MLX]

We do not know.
The Uzumaki may very well be the "clan" of the so6p (dunno if we could talk about clan at that NV era) instead of being descendants of the younger.