If the attesting witnesses, after the execution of a will, become incompetent from any cause, or if the court determines that the testimony of such witnesses is unavailable under the circumstances, the will may be proved and allowed upon other satisfactory evidence.
RSA 552:12
RS 157:12. CS 166:12. GS 175:12. GL 194:12. PS 187:12. PL 298 :12. RL 351:12. 1945, 13:1, eff. Feb. 13, 1945.