For the witness testimony in the lawsuit, parents can simply write down the words "proof materials, XXX is the father (mother) of XXX, and the existing conditions can help XXX raise children" and sign it, but similar witness testimony must be testified in person to be effective. Relevant laws and regulations:

People's Republic of China (PRC) Civil Procedure Law

Article 63 Evidence includes:

(a) Statements of the parties;

(2) Documentary evidence;

(3) Physical evidence;

(4) Audio-visual materials;

(5) Electronic data;

(6) Testimony of witnesses;

(7) Appraisal opinions;

(8) Records of the inquest.

Evidence must be verified before it can be used as a basis for ascertaining facts.

Provisions of the Supreme People's Court on Evidence in Civil Procedure

Article 55 A witness shall testify in court and accept questions from the parties concerned.