My Dad Is 60 Years Old And Overweight. He Does

My dad is 60 years old and overweight. He does not exercise. Two Christmas ago he started having difficulty to pee... after several trips to his Dr. He was diagnosed with E.Coli in his urine. That eventually cleared up with long term antibiotics. Now a year later, since this past Christmas my dad has been having chronic right leg pain radiating up into his groin. Says it's really painful. He has no other pains except recently has started up with lower back pains. What could this be? And should he be concerned?