Please confirm that you have the call drop problem even when your OBi device is not involved, i.e. you call directly from one Droid 3 to the other, using the 9-digit OBiTalk number or the corresponding speed dials.
Assuming that the above is true, you have some pretty strong evidence that there is a problem specific to the Droid 3.
My suggestion, at least for the short term, is to avoid that app and communicate some other way.
You could try a different GV app, such as Talkatone or GrooVe IP. For either, you should use a separate GV account, because GV does not support more than one Google Chat client registered to the same account.
Alternatively, try a SIP app (decent free ones include CSipSimple and SIPdroid) with a free Callcentric account. Though this is more work to set up, it's IMO likely to result in better quality, and is easier to troubleshoot, should you have a problem. Set up the Droid 3 app first and confirm that you can call the 17771234567 CC test number. Then, get a second CC account and set it up as SP2 on your OBi. Call from one to the other and confirm that the calls don't drop. If you get this far, set up a third account for your husband and tell him how to install and set up the app.