Burnham Independence PV

My Godmother have a Independence PV of 10 years and it needs to have its water filled manually every week. She is 80 and no longer able to go 2 flights of stairs. The contractor keeps coming to her house telling everything is fine, and charging her for every visit. I know nothing about heaters but is there any device that can make the water feeding to be automatic? The manual says nothing about it, nor the manufacturer.

I'm trying to find out if this is something feasible before trying a new contractor that could charge for a visit and do nothing - like the one she has now. Thanks!