For the walls below the windows, he used logs, not lengthwise like in
most log cabins and houses but so the ends showed inside and out. That
was his big mistake. The logs had dried for weeks, months, or a year or
two, not sure, but they continued to dry after they were in place, and
shrink, so there were holes almost an inch big that the air would blow
through. He chinked it with cement, that didn't look sot good.


Cordwood construction is a thing -

https://en.wikipedia.org/wiki/Cordwood_construction

... I'd question using it - for load-bearing-structure -
under big expensive windows in a big expensive home.
John T.