Is this a Coumadin Overdose?

My boyfriend who was on Coumadin for 3 years for Pulminary Emboli (blood clots i lungs) and congestive Heart Failure died at hospital 1 week ago. I was called by the hospital and told they gave him a ANTIBIOTIC for Bronchitis and 10 mins later he went into Cardiac arrest. Im not too sure if I believe this or not..Just for the fact that while he and I were there for 8 hours they never once mentioned hm having Bronchitis. ..I leave at 12:30am and at 4:00am he all the sudden CODES due to an antibiotic. When I arrived the next day to find him in ICU (which the hospital never called to tell me or his family) he was on a ventilator and in a coma. I noticed his urine had blood in it and he was SOOOO blown up. (which later in the night i found out it was blood) He ended up coding 2 more times after they injected him with what was told to me to be GLUCOSE ...the 3rd time he coded blood began spewing from his breathing tubes and every little place you could think of. In my heart I feel like something went wrong...Does this sound like he was giving too much COUMADIN?????? he was 108lbs soaking wet before the hospital. When he was pronounced dead he was 136lbs he was so full of blood and fluids. Anyone have any ideas???