I would stick with the super visa, because even if shes here on a trv I would recommend all travelers to get travel insurance. My mother in law had to use hers but luckily she was on a super visa and we had insurance. If she stays only 5 months the portion of insurance that she doesn't use can be refunded less a small admin fee.
Also note that of course with a TRV there is no guarantee of getting 5 months even, whereas as long as follow the rules re insurance etc at least with a super visa a long stay comes with it .
Travel insurance is obviously a given for any North America travel whether TRV or Super even more so for a maybe aged parent.
