Question re: Senior Citizen

If someone had previously been accepted via letter for permanent residence about 30 years ago, can that help them to obtain any kind of status now that they are a senior and planning to move to Canada with their children.

My mom received notices that she could have immigrated about 30 years ago but did not respond or turned it down at that time. Now, I am planning on moving and want her with me. She owns a home, collects social security and would only need medical coverage up there and is willing to pay for it on her own if need be. She would have plenty in the bank after selling her house and her bank account is decent. She would live with us in our home.

Any advise. This seems to be the most difficult aspect of us possibly immigrating.

Thanks for any answers.

Sandy