I wish there was somthing I could offer that would be definitive. There are a couple of option that may be useful for you to look into.
Chronic use of a medication such as
Lovenox - which is a type of heparin that can be given as an injection at home. This is a VERY expensive medication, however, the company does have a patient assistance program for which he may qualify - particularly if he has a RARE genetic disorder.
A research protocol - somewhere like the NIH, or a large university medical center may be able to offer you something.
There is also a newer class of medication being developed as a competitor to Coumadin called
Direct Thrombin Inhibitors. A research protocol may be available with them.
__________________
Please click "ACCEPT" if I answered your question to your satisfaction so that I may get credit for my work.
If you AREN'T satisfied, please ask for clarification or more information.