We don't have any idea without physically inspecting the watch. I suggest you take to expert help. Make an appointment at the Apple Genius Bar for service after the stores re-open. If you need to find an Apple Store - Find a Store - Apple. Also, see How to find your nearest Apple Authorized Service Provider (AASP) or Distributor (AAD).
If the disinfectant caused the damage, then you would have to make a claim against the nursing home. If you have AppleCare+ extended coverage, then it may cover the damage but that would be assessed by Apple.
FYI: These are user-only forums. This is not Apple Support. if you need to contact Apple Support, then contact product and tech support: Contacting Apple for support and service including international calling numbers.
These forums only provide help with Apple products. Thank you for your understanding and support.