What the campaign said
The release for Davis's first 2018 TV ad, archived by Vote Smart, said his record in the Kansas House included protecting veterans' benefits. The campaign's site also kept a veterans issue page at this address and, according to its archived addresses, a November 2017 blog post on helping veterans in need. Neither text is reproduced here, and the campaign did not, in the material we could find, name specific bills.
What we could verify
Not much. Ballotpedia's list of bills Davis sponsored covers only 2009 and includes no veterans legislation. The Kansas Legislature's journals would show his votes on veterans' measures between 2003 and 2015; we have not found a reliable summary of them and do not want to guess.
In the 2018 race
Veterans' issues came up mainly through biography. Steve Watkins, the Republican nominee, is an Army veteran and West Point graduate, and his campaign emphasized that service. If you know of a reliable source on Davis's legislative record here, the corrections page explains how to send it.