Halley's Comet duration of visibility
Typically it was visible a few weeks only, about 3...6 months at most. There is an excellent summary in Broughton (1979). In 1910 the peak visibility was in April, the last recorded sighting of Halley without instrumentation on 13th June.
Yeonan (1986) gives an overview including instrumentation; while it has positional and brightness data for dates in 1911, they are for a magnitude &gt; 10, thus far beyond being visible with the naked eye.
So no, in 1911 Halley was not visible anymore without then bleeding-edge astronomical telescopes.