Overweight Landings
In the Autumn 2007 Flight Safety Focus magazine there is a very comprehensive article which will answer your 'scenario'.
There is no problem or danger carrying out an overweight landing. Aircraft are certified to land at their Max Take Off weight with a descent rate of 10feet/second. A normal landing would be at around 2-3 feet/sec and a 'hard' landing would be around 6-7ft/sec. If the patient needs medical attention without delay then a return and landing will be perfectly in order.
Incidentally, the fuse plugs would be very unlikely to melt if the aircraft lands on the runway of departure. They just might, although not for certain, melt if the aircraft had rejected the Take-Off from just below V1 at Max T/O weight.
So prepare for a landing ASAP and continue as normally. Save the life and be the heroes.
Mind you, you said he's dead so why hurry?