No Jack is not in series 5.
Yes!
Yes, he returned (and with Gwen and Ianto from Torchwood) in the Series Four finale two parter.
Captin Jack is a fictional man, from the BBC series Doctor Who and Torchwood.
The Doctor is never in Torchwood, but at the end of 'End of Days' you can hear the TARDIS and then Jack is in 'Utopia' which is the eleventh episode of series three of Doctor Who
It is unclear if Jack is going to be a doctor because there is no information about who Jack is. A last name is required to fond information about him.
The cast of Come Back Jack - 2007 includes: Chad Cox as Jack Houston
Yes, Captain Jack Harkness asked the Doctor about what happened to Rose Tyler after she was trapped in a parallel universe. The Doctor informed Jack that Rose was safe and happy in the parallel world with her family.
The 9th Doctor's (Christopher Eccleston) companion was mainly Rose Tyler, but he also traveled with Jack Harkness, and Adam Mitchell - but sent him back home when he greedily had an infospike put in his head in an attempt to gain knowledge of future, being the only companion to last only one trip with the Doctor, and never be seen again. Rose was sent to a parallel universe, but still eventually came back, and even though Jack died in the last episode of series 1, he was brough back to life, after Rose had looked into time itself and had the ability to do so, and when she did that, Jack was no longer able to die, and is why he was able to return throughout the series.
In the episode, "The Empty Child." Christopher Eccleston starred as the ninth doctor. It was in season one, 2005. The companion was Rose Tyler, played by Billie Piper.
John Barrowman played captain jack in doctor who. :)
Rose absorbed the time vortex from the heart of the TARDIS and when she went back to save the doctor she said "I bring life" and Jack woke up.
I highly doubt it.