Suggest Treatment For Watery Blisters On The Toe

my dad's big toe turned purple around 8 months ago - the doctors cleared a blood clot in his leg and said that would solve the problem. Since then, his second toe has turned purple and he's in extreme pain. It's got water blisters all over it that peel off. He hasn't had more then just a couple hours sleep every night for the last month because the pain is so bad. Unfortunately he has no health insurance, so options are very limited - what could be causing this?