There is not even close to enough information to provide a useful answer.
As with all international journeys, the passenger should check TIMATIC for document requirements. Access is free through a number of portals. UA's happens to be an easy UI and asks all of the questions in narrative form:
https://www.united.com/web/en-US/app...aspx?i=TIMATIC
Terms such as "layover" and "short" do not mean anything. You will need exact information as it will affect transit and therefore documents.
Indeed if your are flying JFK-DOH-LHR with less than 24 hours at DOH, QR will want to confirm your admissibility or the viability of transit (2 hours vs. 23 hours) at both DOH and LHR.