How to reveal true parentage

Long sto short my character had a secret affair with Daenerys while she was married to Viserys and resulted in a son. The son was a Prince but third in line. Now hes next in line with a dragon and lowkey looks like my character with White Hair. I have cancer and am on deaths door, is there a way to reveal the secret? Also Danyerys died during the birth of our second child. I have 5 other children with Margery that are spread out across Westeros representing Dorne. HELP!