I have a lot and lot of experience in the processing of visit visas for a lot of my friends and family. Based on my experience, this is not at all a solution. The criteria for the issuance of supervisa is more difficult and strict. If she failed to obtain a normal visit visa, the chances of getting a supervisa are very very low. If she already applied twice and rejected, this makes her case more weak.
My advice is to address the specific issue/reason on which she was refused previously because thats the main thing which is appearing in front of them and they will do the same thing with the supervisa application as well if that issue is not addressed properly. Whenever you reapply the visa, you have to prove them "wrong". In order to do this, you have to support your application with enough proof and documents and must not give them even a 1% chance to doubt it and this is how you can make it a success. I dont know what was the reason of the refusal in the previous 2 applications but if you need my help reply it and i will provide you my email address and glad to help you for your mom