Your life story reads a little similar to mine. I have 5 kids and I just abandoned a live in flip because it was too much to do while actually living in it. We've done it in the past, but since this house was built in the 70s, it was just a little different than normal. This one came with 20 acres, so as it moves to a more traditional BRRRR, there will also be some income opportunities in the mean time.
It shouldn't take much more than a written and signed lease plus your brother receiving some mail there to prove to the VA that he lives there. I recently got out of the Army in 2021. The threshold for proving residency was pretty easy.
Without having all the information, I would go with the cheaper option. If the break in the supply line is after the meter and on your property (not on the easement), then it may even be easy to do it yourself by renting a small jackhammer (or buying one from Harbor Freight), exposing the line, and replacing it yourself. It's very labor intensive, but I did something similar with a drain line in the basement last year with that live in flip. I'm about to fix a water supply line by digging with a shovel and throwing some new pipes in there. My supply line cracked because a dump truck drove over it after a good rain. It's buried deep enough, but the ground being soft made it more malleable. Cost to fix is three hours and $15. It would be less than an hour if I rented one of those small back hoes, but I have more time than I really need these days and I think it grounds me to get into physical labor sometimes. It definitely makes me less entitled when negotiating with my contractors about the cost of something when I know how much work goes into it.