High Clink78
Can his cancer wait 4+ months for you to grow out plants then make something with them that's going to help?
Hemp is a poor choice to grow to get your CBD as CBD rich cannabis plants will yield a lot more oils and won't need 12' of head room to grow in. It is generally thought that THC is the more potent cancer fighter so a strain that is higher in CBD than THC would likely work better than CBD alone. Much easier to source CBD rich cannabis strains than hemp as hemp is a smaller and very regulated industry and the seeds aren't offered at cannabis seeds vendors sites. A high CBD autoflowering feminized strain would probably be your shortest route to getting your own home-grown CBD products other than buying them from a producer somewhere.
Remember that hemp oil from seeds has no CBD or THC and tho it's good for you it's no cancer cure.
If regular pot is made into an edible product like a coconut oil extract without being "activated" the medicinal qualities are supposed to be the same or even better and there is much less intoxication which is easier on patients that get all messed up and don't like too high a high, like myself.
There's lots of other things that can help fight his cancer.. Google "baking soda and maple syrup cure" or "baking soda and molasses". Many other non-pharma and inexpensive aids to fight cancer out there too. Maybe check out naturalnews.com and find their research link to search for alternative cures that are bladder cancer specific.
Fingers crossed for your dad's recovery and kudos to you for helping him out.