I am very sorry for your loss.
Generally it's a choice between Medicare reimbursement or VA, particularly if you did not get authorization beforehand from the VA to use a particular facility. If you are the representative of your father's estate you can always file a claim, but the chances of success are pretty slim.
I'm including a link below to a publication that explains this, but also has some phone numbers (pp 19-20) you can try for more information. Good luck.
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