Please help my precious wee Elmo who's had a rocky start to life

Christmas time 2010, Elmo was dumped on the local vets doorstep with only half a tail. As it was Christmas time and no vets would have been there to look after him, I took him home where I fell in love with him and his lovely nature, he follows me everywhere, such a cool wee boy. In 2013 he has 2 life threatening urinary tract problems within the space of under 2 weeks, he is very lucky to be alive and has been on a strict urinary tract diet since. Then last night he started acting strange and he seemed sore, so first thing this morning I took him to the vets, where he needed an X-ray of this pelvis as the vet thought there was a problem with this back legs. The vet has since called and said his pelvis is fine however his spine has trauma, likely from tail pull when he was very young and now how secondary arthritis in his spine due to the trauma. It breaks my heart to think of all he has endured in his little over 5 years of life and he deserves to be pain free for the rest of his life. Please help my gorgeous wee boy with his on going treatment costs, he's come this far he deserves a pain free rest of his life