well, i don't know everything, but we've had cats over the years, just my
1. male cats do "spray" to mark their "space"---they do it less if they are neutered.
2. once a cat urinates in a specific spot it is difficult to prevent it unless the area is immediately cleaned and animal repellant is used...sorry if cat pisses on carpet you almost have to steam clean it.
3. advice about cleaning litter box daily to get the animal acclimated to new surroundings is valid---if animal is traumatized from injury training will take longer.
4. a cat can be trained to successfully use the toilet---many young cats have been trained this way---i do not know if the technique is successful with older cats.
http://www.potty-cat.com/index.htm?catalog.htm&1
5. kudos to you for helping an injured animal.