Exogen 4000 advice needed!

Hi all, I am desperate for some advice about a screen display on a rechargeable Exogen 4000.

My son has a nonunion scaphoid which is in danger of ruining his life plan as he is half way through a university course in Outdoor Leadership and Coaching, which he has invested a lot of time and money in. He is due to have a graft and screw op, but the surgeon says he cannot be sure it will heal....ever! I want to buy an Exogen 4000 for him to encourage a succesful outcome and have found a used one I can afford.

The problem is that although it has only had 49 uses it has 390 days registered when no treatment was used and it also displays a yellow 'no treatments remaining' screen with additional info, please take a moment to look at this.

Bioventus Exogen Ultrasound Bone Healing System | eBay


If anyone is in a position to advise me whether buying this would be money wasted or not I would be very grateful.

My thanks in advance AlexC