peripheral artery disease

My 81 year old husband had a stent placed in his left heart artery six months ago. He now is suffering from PAD symptoms. They are worse at night when he is down. His left leg will get painful,numb, and freezing cold. It will get so bad that he has to get up and walk around.
In the day when he is active it is much less severe. Is the reverse of the norm significant? I've read most experience the symptoms when active. He also gets severe headaches at times for the first time in his life. Need to be worried?
Thanks,
Rikki