[X][Emma]Yes
[X][Danny] Tell Danny about what happened to the Camp.
In all seriousness, telling Danny about the Watch is a pretty bad idea. If it were just ordinary superpowers, that'd be swell. However, him behaving like a responsible parent here would be detrimental to both Taylor's and his own safety, and Taylor isn't going to be able to convince him of that.
Is the Watch Tinkertech or actually from space? Is Taylor Mastered or otherwise in danger from it? Can the PRT keep her safe from whoever's looking for it? Regardless of how much if any of Taylor's story he believes, from his perspective, clearly something must be done. But against all convention or common sense, the most prudent action here really is to do nothing about it, which is the one thing he as a parent will not be able to do. At least not without destroying himself with worry/other unpleasant emotions.
The best possible outcome would be to tell him about the Omnitrix, have him not blow our cover, and actively participate in Taylor's researching and upcoming heroic lifestyle. But... Taylor's fourteen. What parent of a fourteen year old isn't absolutely certain that they know better? Especially when their child's safety is concerned?
So that's just not going to happen.
Maybe later when Taylor has both a better understanding of the situation herself, and some corroborating evidence to back up her outlandish claims, she can tell him without setting him off into panic mode.