Weird Dark patches at the ankles and feet?

My Dad is 50 years old and for about 1 year and a half he has had these Strange Dark patches at his ankle/calve he used to work in a factory w/ metal. He was a welder I think.He was put off. The dark patches have faded a bit but they are still there. I've heard this is bad circulation. I also noticed recently that he has these strange bumps on the tops of his feet They are purple-ish blue. He said they were veins but they don't look like it. He's sorta overweight but he's started exercising. Any Ideas? Please help I don't want to lose my Dad.