Ok, I know what you have, my sister has the same thing and I went to her place today to check it out.
It is a 510 fitting. I used a SR 510 and LR 306 atty on it with no problems, also used a SR 510 carto. Not sure that I would advise using a 306 as i did, it was Low res, and it fired it ok, but for regular use, I would use a standard 510.
Now what I did for her, was to find a joose that she liked, that was similar to what she had in there. It tasted to me like a RY 4. A tobacco flavor kinda sweet. So I took a syringe and filled it with 1 mil of my RY4.
The orange part of that ecig is an atty that is totally enclosed. Meaning you can't seperate the atty from the cart. So I cheated and filled from the bottom. From the bottom where the threads are, there is a small hole there. I slowly added drop by drop the liquid in the syringe. It took approx .75 ml.
Not sure how long that will last you, it lasted her 2 days initially. So now she is able to order some more regular attys from somewhere else, as that place is way to pricey.
She seems to like the unit, just not the price of the refills.
Hope this helps, and sending well wishes to your hubby and you.
Debbie
Edited to add: This is the web site my sister got hers from:
E-Cigs: Electronic Cigarette: E-Cigarette Kits, Accessories & Nicotine Refill Cartridges