Hello Sandra and welcome to the site.
Gleason 3+4=7 is much better than 4+3=7 so that's in his favour.
Do you know what his PSA score was as it also helps with advice.
You mention primary scores so does that mean they said the cancer was only on one side of the prostate?
Once the scans are done you'll all have a better idea of how to proceed.
As he others have said try and download The Toolkit from publications or ring and order a hard copy. It's always handy to have it available.
Mostly though I just want to say don't panic. Everything you feel now has been felt by all of us, whether we be the patient or a loved one helping and supporting that patient, so never feel alone .
Once the information is back and the specialists have given dad their opinions then you can go from there. Prostate cancer is a bit of a rogue in that it doesn't affect all men the same, even if they had the same scores and tumour and positions the same. You could have somebody with PSA of 2.5 with aggressive spread so try not to second guess what could happen
My own husband had Gleason of 3+4=7 and was treatable.
Try and keep calm. It's good that your dad has you supporting him. Anything you want to know then please ask.
Somebody will have the necessary experience
All the best from another
Sandra