Do you know if a mans testicles get bigger with age? Is it normal?

My significant other is in his late 50's and his testicles are biggest I have ever seen. When he sits down, they bulge out the side of his pants. His get lost inside if his big testicle sack unless he becomes erect. He gets a rash down the medial side of his legs from the heat and moisture. I told him he needs to wear tighter shorts or a jock strap to support them. Is this normal or does he have something wrong with him? He is about 75 lbs over weight.