For someone who is considering using a cannabis/hemp product for a purely medical reason, buy something at a shop or online. For the first time, at least. If you hand BF a joint of a CBD strain you grew, how much CBD is he getting? Is it enough to help? Is it more than he needs? A measured dose will give him a baseline of what he can try to help.
If the purchased CBD doesn't help, you have wasted a little money instead of whatever blanket investment you have in growing a CBD plant.
I don't know where you are so going to a dispensary might not be an option. But CBD seems pretty well accepted these days and can be bought online.