Thank you to all who have posted ideas! I'm definitely taking notes and will share them with Randy. He does want something totally homemade so that he doesn't have to deal with cans/bottles of V-8.
Excellent idea regarding keeping the tomatoes intact until ready to blend for the powder. I do want to send my brother home with some, so it will have to be pre-blended at that point. I'll just vacuum seal it before he leaves, and have him put it in his checked luggage. I do have oxygen absorbing packs to keep it mostly moisture-free.
The plan is to keep it as low-sodium, low sugar as possible, with no MSG. MSG is in everything these days, along with her nasty little sisters. Label reading is an absolute must for me since I get migraines from it. I won't be drinking this, but I will use it in a soup base.
I can't wait to get to Sprouts this weekend to get the produce and make my 1st attempt.
I promise to keep you all updated. And please keep the suggestions coming. They are most helpful and appreciated.