If his Cancer was service related, such as Agent Orange, then he will continue to get disability for any Cancer related issues. My guess, because it has to be service related, is that he is getting it for the problem in his back. Contact your local DAV group or the VA itself for information on your dad's disability payments.
My husband receives $250.00 a month for a service connected disability, back, he is considered 20% disabled. But as he is retired military, they immediately take out $250.00 from his retirement pay. No double dipping allowed!
Dx Feb 2010 4 cm tumor, just inside rectum
EUS stated T3 tumor
2nd opinion, need better path
Mar 2010 transanal surgery. Surgery by board certified CRS found tumor only in lining
6 exams of surg site, 3 PET, 3 scopes laterNED.
Scope in Mar2015, clean colon
Next scope/test in 3 years