Down to the .38's...
COLT = 6-shots. 1 more round. 4 less oz.
Extra round, less weight to absorb recoil or carry. Slightly bigger gun. Still have to 'pull back' on the cylinder release latch ( and the cylinder goes around the 'wrong way'
)
RUGER = 5-shots. 1 less round. + 4 oz.
Is it really 'less' when it comes to holding steady?
Nice to have the very slightly less 'bulk' dimensionally.
Easier to 'press the button' when releasing the cylinder latch.
( cylinder rotates...really doesn't matter which way, that was a joke
)
I have owned a RUGER SP-101 and can tell you there is a certain 'heft' to the gun that just FEELS GOOD...confidence inspiring, if you will.
HOT .38's would be a great choice, if MOM wants to try that.
Of what you listed, I'd pick the RUGER.