How Can Trichomoniasis Develop Non-sexually?

The Dr. office called and said my boyfriend has Trichomoniasis. He had blood in his urine and did a UA. Some history: He had a UTI aprrox 4-5 weeks ago was treated with antibiotics it cleared up and about 2 weeks after the blood appeared again but not as prevalent. Which led to the recent UA that they called and said he has Trichomoniasis. Everything I read says it is usually a STD and sexually transmitted. Here s the problem we see. He is 73 years old has ED and our love making consists of using our hands. He is diagnosed with Kidney disease stage 3 no systems, had bladder cancer with surgery a year ago, on oxygen and has severe emphasemia. Is there another way for tric to develope? They gave him one treatment of Metronidazole 500 mg.