The captive ferrule fitting can be removed and reinstalled repeatedly- - - -once it squeezes down on the tubing, it doesn't have to be removed again. It just swages down and puts a slight groove in the tube. The simple fix for the broken tube is to put a short piece of 1/4" OD copper tubing over the break and solder it into place. It's a quick, permanent fix, and it will be much better than a piece of rubber tube.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!