First we need to see atleast the xray of the patient to check for any mal alignments of lumbar spine or some disc derangements. A full routine schedule would also be helpful for the appropriate treatment.
Till then you can give hot water fomentation with hot wet towel atleast twice a day and lie down on the back with pillow under the knees for atleast 15 minutes which can help your mother to relax her low back muscles.
Next Steps
Approach a nearest physiotherapist for a confirmed diagnosis and start the treatment asap.
Health Tips
Dont bend forward to pick up any thing and try to change position every 15 minutes. Example: if she is sitting then getup and walk few steps then again she can continue sitting similarly if she is standing for more than 15 minutes then she can sit for a minute and continue standing again.