I see you're the same one who asked about Bradley. Given a disability I'd say this:

(1) For you traveling out: Taking the train to Hartford and then the (dedicated, nice, clean) bus to Bradley is perfect. Personally I travel out of JFK more often, but I'm very comfortable with using the NYC subway system to get from Grand Central (where the new haven line terminates) to the airline access at Jamaica Station. This could be overwhelming to try for the first time, and it's a longer trip than BDL anyway.

(2) For you mom traveling in: If a bus isn't a barrier, then same deal with BDL. If a bus is an issue, then use Newark + Amtrak. I suggest Amtrak in this case because it's direct to New Haven. You could take NJ transit + subway + CT transit instead, but I wouldn't recommend it even for the able bodied if it's all new to you.

Ultimately, it's very easy to fly out of New Haven. I mean, we're talking about Bradley, JFK, Newark, others there mentioned Tweed (great if they have your flight), that's a lot of airports you can get to with public transport in max 3 hrs. How often do you drive 3 hrs to get somewhere in the Midwest, right?