Good points, Skid..
That said, Op should advise his pal to take the lessons learned from the situation -and seek every possible method he can afford to ,to get into a "never again" mode. Life is no longer a "what if" is has happened-it;s time to become a gunfighter (when needed)
1) Situational awareness- ie: stay alert, stay alive. Even at "home" or wherever you normally feel safe- you need to be aware of who/what's around you as much as is possible. He needs to learn to look past the obvious ("oh, there's no one standing beside my front door") to thinking like the bad-guys ("if I were to target ME, where would I lie in wait?,how and from where would I approach?.etc")
2) Gun-up and train-up. Get equipped with what he can afford and handle, learn how to use it to the best of his abilities,look into his local laws regarding carry (if-any) and carry OC and/or CC 24-7, even IN the house.
If Sky is also armed, or knowledgeable in being so- train him-show him what you know, or set things up to learn and train together -as partners.
3) Murphy-Proofing- have a backup, and backup plan to the backup for when that fails.Not just for the gun of choice, but in preperation to go hand-to-hand, knife to hand, blunt object to hand, etc.
On the same note-if he arms up, have him invest in some snap-caps, and learn to insert 1 or 2 -at random-into every mag. or every other mag- to learn to deal with failures to fire, clear malfunctions, and so forth. (good habit to get into) -also have him train (and train yourself) to shoot with either hand. Shoot left-handed one mag, right handed the next, etc.
4) Get out of whatever he's up to or invovled in that brought these guys to his door, or if that doesnt apply, learn to be more discreet with any valuable items that may draw someone to your place.- (most home-invasions of this type are commited by folks who know you-or at least know what possesions you have that they may be after/it is rare, in the extreme, for any home-invasion type robberies to occur at random, by strangers-ever.).