I'm not familiar with Alliance College, but you should first contact the school, and then the
alumni association. They do flash the TKE crest on their website so there's probably a chapter there. You can also look up chapters by state at
www.tke.org . Many local fraternities, which is what I assume your father-in-law was in, got absorbed into TKE in the 50s and 60s.
However, if your father was not a member of the local when it became affiliated with TKE, he is not technically a member. You can contact the chapter though and ask them about honorary membership, but if he's near his deathbed, the process is probably too long for him to realistically become a member.
But yeah, contact the alumni at Alliance, it's definitely your best bet.
-Jiffy
Gamma Mu #646
Epiprytanis