I'm in desperate need of advice and the can't find anything helpful on the internet!

The situation is this: Recently, a friend of DH told him that his company is looking for people who do iPad development, which DH has been doing for years. He's had an informal phone interview and spoken with their "Talent Director" both of whom said from their perspective he'd be offered a job making 50% more than he currently makes, but there are a few more hoops and formalities. He has not received an official offer.

The big question is - when should he tell his current boss. He really likes his current manager and they have a really friendly relationship. His manager also strongly values him as an employee and has told him numerous times that he's the strongest asset to the group (its a group of 10 or so people at a large international company). DH wants to be respectful and tell his manager as soon as possible so that the manager doesn't feel betrayed or lied to. However, he also is worried about saying something before he has an official offer, because what if it falls through - with that hurt their work relationship?

Another issue is whether or not his current manager would seek to offer a higher salary. We think its a strong possibility, in which case, the more lead time he has the better (since it is a big company and its not just up to him - it would take time).

DH has asked me what he should do, and I have no ready answer for him. What do you all recommend? Has anyone been in a similar position?