A quart is 2 pints. A pint is sixteen fluid ounces of water and weighs about 16 ounces (avoirdupois weight.) A gallon is 4 quarts (8 pints) and thus weighs about 8 pounds. Five gallons would be about 40 pounds.
In some cases, if your mother is on Medicaid, she can designate you as her personal home care aide and you can get paid a small amount through Medicaid. If your mother has her own resources, you can draw up a contract agreeing to work as her home health aide and she can pay you a salary that you both agree upon.
My mother has nothing so I don't take care of her in hopes of getting anything. I actually worry month to month about the finances. My sister told the police a bunch of lie's about me to get me away from my mother so she could take over total control, put my mother in a nursing home and take control of her townhouse.