Dear costumer, i’m very sorry to hear about your husband conditions , I send you my best wishe to you, your husband and your family…
In the time frame of 3 to 6 months the doctor say he as left it’s hard for me to recommand that you can grow something, he need help now, not in the 3 to 4 months that a growth will take…
So, here some strains with very high CBD content (as much as 20:1 ratio)
AC/DC
Charlotte’s Web
Harle-Tu
Cannatonic
Those strains are renown for their ability for seizure but, also have cancer fighting capability shown in laboratory…
Other strains that have a 1:1 ratio are use to fight cancer as well since THC demonstrate some cancer fighting capability too. Here they are
Pennywise
Canna-Tsu
Stephen Hawking Kush
One to One
Nordle
CBD MediHaze
You can also try CBD oil, this site sell a 5% one… In Canada, we have access to 20% CBD oil extract that work great for me in combination with some 1:1 and Home grown Chocolope from ILGM for my chronic cluster headaches…
You most probably can find all the strains listed here “ready to use” , including oil extract if you live in a country that give access to cannabis… Just “Google” them…
or ask your local dispensary…
And I will had to the wonderful suggestions made by @Majiktoker and @Hogmaster, go with a pure indica strain like Afghan (ILGM have the seeds for this strain) for sleep aid…
Hoping that’s my modeste contribution is going to help you , my prayer is gone a be for you, your husband and your family and hoping for the best , and may God be with you in these difficult time…
~Al 

P.s. I am not a doctor and I am closely monitor by a neurologist and my family doctor in the use of cannabis and this is my opinion and my own only and does not involved ILGM in anyway since it’s not a medical involved site… I or ILGM do not recommand any dosage and it’s a trial an error thing and every one respond differently to cannabinoïds.