I'm not sure if you guys already have rifles or still looking to get them.
I'd advise a 7mm08 and make sure your rifle is zeroed.
Practice enough that if you only get one shot you can make it count. Practice can be fun for you and your brother.
Plan on making several trips, before the season, to do some scouting around that cabin. Check out the food sources in the area. Deer usually head towards the food source later in the day.
Calif. is a long way from PA ( Where I'm from) so I'm not sure what those blacktails eat there
If there are fields in the area, your brother and you might want to watch them some evening to see what you can see before the season.
Just try spending some time there to get a better idea of what the deer do there and when they do it.
I'm not sure if baiting is legal there but it might be an option under the circumstances. Baiting is frowned upon by many, but, I'd think that in this situation, it would be understandable.
Wish I could be more help. I know I'm just covering basics here but I'm not sure of the terrain and food sources in your area.
I wish you guys lots of luck and prayers will be sent your way.