I'm not an expert on the medical benefits of cannabis to an autistic person, but I was thinking that high THC varieties might be a bit of a shock to them. If the person is severely autistic, as you say, they might not like or understand the effects of high THC cannabis. Blimburn rates their GDP as 25 to 35% THC. I doubt it's above 25% myself but that's a lot of punch for someone who is new to cannabis and may not understand the effects that they are experiencing. Have you considered high CBD varieties? Lots of them on the market now. Many have CBD levels of 15% or higher with THC at 1% or lower. They don't get you high, they just medicate. I'm into high THC but I have a CBDiesel from Crop King going now and I'm pretty curious as to how it will taste and feel.