Under the circumstances you describe, it may be worthwhile for your husband to be seen by a urologist. It's good start that he is being seen by your family doctor, but a urologist might be able to provide more insight especially if a urologic cancer is suspected. The symptoms for testicular cancer are described here. Kidney cancer is a bit more difficult to diagnose, hence the need for a professional to take a look at that.
"Life moves pretty fast; if you don't stop and look around once in a while, you could miss it." -Ferris Bueller
11.22.06 -Dx the day before Thanksgiving
12.09.06 -Rt I/O; 100% seminoma, multifocal; Stage I-A; Surveillance; Six years out! I consider myself cured.