To be fair to Invictas - i think you maybe phrased your Question a little carelessly, and sometimes this can infer a degree of heartlessness which is not intended, or felt. It's the penalty we all pay from time to time - minterperetation of our thoughts due to the limitations of printed exchanges.
I think having children is a gift given to some, and not to all. I do agree with LoftyLottie - as i have done for many years (Hi Lotts!) that nature has built in a cutt-off point for conception for simple practical reasons - the health and strength nedded to bear and raise children diminish with age - i am a grandad of fifty-six, and the thought of my grandchildren full-time is not something i would contemplate with ease!
I think given their close family, and fanancial security, that ms. Preston will be fine with another baby, and hopefully a new arrival will help to assuage their terrible loss, although (and i am sure you regret using the term0 - replacement is never anything to be considered for even a second's thought.