Sipping through a straw is a pretty complicated manuever. Your tongue and lips have to hold this position, your cheeks suck in just so much, your soft palate and throat set up - a lot is happening there, and it has to be coordinated, too! It is like an early yoga posture, effortless for anyone who's practiced a bit and in good shape, but for a first timer or someone with less than full ability in all those little postural and instrinsic muscles, difficult and tiring.
Sipping through a straw is considered a bad idea with bulbar/pseudobulbar symptoms, anyway, because it increases the chance of aspirating the drink in a decent quantity.
That said, in terms of holding the cigarette in her mouth, it seems to me like a similar challenge to holding and using toothbrushes in quads. Normally they use foam to build up the handle to be big enough to require little coordination. I've never seen anything like this, but I'm imagining a larger, softer thing with a cylindrical hole through it for the cigarette, made of non-flammable material. It wouldn't be worth spending a lot of money on, because it will only last so long - she'd need some jaw strength to use it, but if you could figure out how to make it cheaply, it might work for the meantime.