You definitely do not want to do what you offer, it re-installs the branch masteron your employee master. Depending on what your colleague was on master, you can often rewind the center one master.
What you can do is vice versa, reinstall your colleague’s master before merging it into a master.
git fetch coworker
git checkout coworker/master
git rebase master
git checkout master
git merge HEAD@{1}
git push
. , . , , , , , , , .
. , , , refetch. , , , .
, . , , . , , , . , , , , . , ( !) "".