In the wake of Anne Heche’s death, the legal battle between her son and her ex-husband over control of her estate is heating up.

As People reports, Homer Laffoon — son of Heche and her first husband, Coley Laffoon — is disputing the validity of a document that Heche’s second ex-husband, actor James Tupper, has claimed is her will.

According to court documents obtained by People, Laffoon’s attorneys have filed a nine-page supplement to his already filed petition seeking to assume control of his mother’s estate.

READ MORE: Anne Heche’s Ex James Tupper Files To Pull Estate Control From Her Son Homer, Alleges Family Rift

Laffoon, 20, alleges that Tupper, 57, has been blocking his attempts to communicate with Tupper’s 13-year-old son — and Laffoon’s half-brother.

Laffoon is also disputing that a 2011 document that Tupper considers to be Heche’s will, naming the “Men in Trees” star as administrator of the late actress’ estate, is valid; Laffoon claims that the signature on the document isn’t his mother’s, and was not signed in the presence of two witnesses, as required by law.

“Mr. Tupper repeatedly refers to the email attached to the Objection as a ‘will.’ However — as a matter of law — the email does not qualify as either a holographic will or formal witnessed will,” Laffoon’s latest legal filing reads. “The email fails to satisfy the legal requirements for a valid holographic will because the material provisions of the purported will are not in the handwriting of the Decedent. A will is valid as a holographic will, whether or not it is witnessed, if the signature and the material provisions are in the handwriting of the testator.”

READ MORE: Anne Heche’s Eldest Son Left With ‘Deep, Wordless Sadness’ After His Mother’s Death, Shares Heartbreaking Statement 

Laffoon’s filing also contends that the so-called will “fails to meet the requirements for a valid holographic will because the signature and material provisions are not in the handwriting of the Decedent. The email fails to satisfy the legal requirements for a valid formal witnessed will because the email was not signed by the Decedent and does not have two witnesses who signed the document during the lifetime of the Decedent.”

As a result, the filing continues, “there can be no nomination of an executor” given that an executor “is appointed to administer an estate pursuant to a valid will.”

Neither Tupper nor Laffoon have responded to People‘s request for comment.