New to site and have some questions

hello everyone

I play Banjo and Mandolin

I am searching for my first Dulcimer and have a few questions  

#1- I am looking for a Dulcimer for my wife she has Dementia so I am looking for something to make her mind work I figure what better way then with music, from what I have read a Dulcimer is fairly simple to learn don't know if that is actually true, and I do not want to confuse and frustrate my wife with her dementia,I have kind of taught her amazing grace on Mandolin but mandolin is fairly difficult for her and she got frustrated with it fairly quickly, her learning curve is rather slow,April 2019 she was hit by a hit and run driver which accelerated her dementia 10 fold, but I think it would be worth the effort for her just to give her mind an exercise to do

#2- does the shape of a dulcimer have an affect on sound or volume like for instance a tear drop dulcimer and a hour glass shaped dulcimer ???

#3- what is the difference between a standard Dulcimer and a Baritone Dulcimer ???

The one thing I do know is I do not want to purchase a hammer Dulcimer

any help with this would be greatly appreciated

I have been looking at some from one of the builders on this site they look nice but I am just really confused as to what to even look at when it comes to a Dulcimer I have no problem in spending the money for a decent Dulcimer but I want to purchase the rite one that would make it easy for my wife.

Thanks for reading