This is very similar to the symptoms that my husband had and he was diagnosed with a depp vein thrombosis (DVT). Your DH needs to see a doctor, this is a very dangerous but treatable condition. If it turns out to be a DVT, your DH should ask to be genetically tested for hypercoagulation ... that was my husband's problem which was not discovered until a year after the DVT and he threw clots to BOTH lungs. The genetic problem can be inherited by your children; my DD has needed to take blood thinners during both pregnancies to prevent miscarriages.
If your DH's family has a medical history of strokes, varicose veins, or miscarriages then he needs to be tested. MY DH's mother died of a stroke and had a history of miscarriages and varicose veins, his brother also had a DVT.