What beginner device do you think is the best for a smoker moving to vaping?

Hi guys,
my Dad has to quit smoking due to a stroke.
He has tried a vip photon and an innokin endura t22 and now has an innokin coolfire iv 4 tc100.
I read that the coolfire 4 can only be used with 6mg nic liquid as maximum.
He still has the odd ciggie and I can't seem to find the right settings for him.
personally I think the coolfire is too advanced for him but the endura which worked for me didn't do it for him.
He used to <a href="http://www.vapininthecape.com/eliquid_c_7.html”>smoke around 10-15 b&h a day.
What nic level would you advice and…

<a href="https://www.planetofthe<a href="http://www.vapininthecape.com/eliquid_c_7.html”>vapes.co.uk/forums/new-users-corner/new-user-questions-and-discussion/threads/what-beginner-device-do-you-think-is-the-best-for-a-<a href="http://www.vapininthecape.com/eliquid_c_7.html”>smoker-moving-to-vaping.141372/”>What beginner device do you think is the best for a <a href="http://www.vapininthecape.com/eliquid_c_7.html”>smoker moving to vaping?