Spoiler (Highlight to Read):
Yes, and he does indeed show up in Suikogaiden Vol 2 which is after Suikoden II. Officially though, the creator of the series said the ending is open ended and that personally he believes the proper ending is the one in which he gets killed, Nanami is really dead, and Riou becomes President of the Dunan Republic.
Same story with Gremio's death in Suikoden I. There is no official ending. If you saved him, then he shows up in Suikoden II. If not, then he's dead. Pahn did survive, even though he can be killed in Suikoden I as well. He shows up in Suikoden II regardless. Gremio's death probably would have made me cry if I didn't hate him and was overjoyed that the game didn't force his useless ass in my party anymore.