Blunt honesty is best in a spot like this.
No offense to the makers of any vape listed here already... as I use them all and love them.
If going with a log vape, I believe firmly that Nylon stem with stainless steel tip is the route to take.
These were the standard for Aromazap, and for the now extinct Woodeez. Purple Days also used this style, although a slightly tighter size.
The issue with most senior patients is that after a time the screens get clogged.
Many patients are diligent about keeping the tube clean and they do well.
Some allow the clogged screen to grow, and they run into the need to clear the stem with a pointy tool.
The screens can be poked out and are difficult to get back in (for a patient with limited dexterity)
If they can do that regular maintenance I would say UD (Underdog) is a good bet!
My greatest successes have also included the Solo.
The Solo is a patient pleaser.
It has a solid feel that makes a patient feel confident.
No games or trickery with the stem. it goes in easily, and is cleaned so quickly and smoothly (especially the straight stem.
The solo also has an auditory signal to help keep a senior patient "on task".
It beeps at session's end, making it a convenient reminder.
The buttons are easy to hit even for the most impaired hands.
@PlanetVape makes stems that are available in a shorty GonG type, which is a very thick and solid choice for a patient... not to mention
@Ed's TnT having some solid wooden choices for the solo.
The solo also is a solid home vape so it doubles as a portable and home unit.
If the unit is for continued home use only, the choice for me would be the UD Vaporizer with Nylon stem.
If for use around the yard, and home and even in the bathroom..... or while being whelled about in the garden.... Solo would be my choice.