Can Halley's comet help scientists predict the future?
Apart from things directly related to the comet, no. Since the
comet has a regular orbit, it is possible to predict when it will
be visible. Halley's Comet is also the cause of the Eta Aquariid
meteor shower, so the passage of the comet may result in an
increase in the shower's intensity.
In most cases, trying to predict the future based on the
positions of celestial objects falls under the field of astrology,
which is a pseudoscience.