I would appreciate to hear your thoughts.
1. Own a dog! We used to keep highly trained Pit Bulldogs in the house with us; and, yes, back in October of 1990, bright and early on an otherwise quiet Sunday morning, those Pitbulls actually saved our lives when our home was suddenly invaded. (I didn't have to do a thing; the Bulldogs did it all.)
FerFAL, the Argentinean survival expert, recommends keeping one large dog like a Pitbull, and one small loud dog like a Dachshund. (Which, at one time, we also had!) I think he's right: Pitbulls make really lousy, 'watchdogs'. Why? They're simply too confident. On the other hand our Dachshund was extremely alert, had a loud deep voice, and alarmed very well. While he was with us nobody could get within 25 or 30 yards of the house without him knowing, and immediately sounding off.
2. Because we've already had the displeasure of experiencing a home invasion (and vividly remember all the details) I'm almost never out of reach of a fully loaded pistol while I'm at home. I, also, carry all day long; so I regularly come onto, and leave the property while fully armed. (It's been, literally, decades since I've come home and haven't conducted a security check of the premises BEFORE settling in.)
I've studied dozens, if not hundreds, of these incidents and have formed the conclusion that home robberies and invasions are usually over very quickly; AND, wherever gunfire breaks out, the bad guys tend to get out of the home and off the property very quickly. At the most, the whole event tends to be no more than a two or three minute affair.
In the subject incident? Hey, once they've, 'got the drop on you' I'd have to say that discretion is the better part of valor. I'm glad your friend remained calm, cooperated with the thieves, and got them out of the house as quickly as possible. The only thing that bothers me is things COULD, very easily, have gone the other way. Glad he, his friends, and family got through everything OK!