(1) If any person who attests the execution of a will shall, after its execution, become incompetent to be admitted as a witness to prove its execution, the will shall not, on that account, be invalid.
(2) If a will is attested by a person to whom, or to whose wife or husband, any beneficial interest in the estate is devised or bequeathed, and the will cannot otherwise be proved, such person shall be deemed a competent witness; but such devise or bequest shall be void, unless such witness would be entitled to a share of the estate of the testator if the will were not established, in which case he shall receive so much of his share as does not exceed the value of that devised or bequeathed.
(3) A will may be proved by the testimony of one (1) of the subscribing witnesses without regard to the availability or competency of the other witnesses, provided said will was acknowledged or subscribed by the testator in the presence of two (2) witnesses at the same time.