@Daryl95 First of all, I am sorry that you have had an accident and do wish you a speedy recovery with hopefully no long term effects.
With regards to your reservation, it sounds as though your host is unwilling to refund and wishes to stick to their cancellation policy which you agreed to when making the reservation. From their point of view, you have had these dates blocked from other reservations and at this late date it is unlikely that they will get those dates rebooked out. They will still have bills to pay etc.
You have several options here. You can either leave your reservation in place in which case your host cannot book those dates out to someone else, or you can cancel and the hosts calendar will be open again for possible bookings. Some hosts will try and work with guests in this situation by perhaps refunding any cleaning fees or agreeing to refund any nights that they are able to rebook out.
If you took out travel insurance then you may be able to make a claim there and I am sure your host would happily supply any information you may require to support this if asked.