The true point of no return has to be indeed much later than we believe it to be now.
Who is “we”, and what do “we” believe about the point of no return? Surely you’re not talking about ordinary doctors pronouncing medical death, because that’s just irrelevant (pronouncements of medical death are assertions about what current medicine can repair, not about information-theoretic death). But I don’t know what other consensus you could be referring to.
Use a prefix-free encoding for the hypotheses. There’s not 2^n hypotheses of length n: Some of the length-n bitstrings are incomplete and you’d need to add more bits in order to get a hypothesis; others are actually a length <n hypothesis plus some gibberish on the end.
Then the sum of the probabilities of all programs of all lengths combined is 1.0. After excluding the programs that don’t halt, the normalization constant is Chaitin’s Omega.