For those who recommended travel insurance which I also subscribe to and have annual travel policies, I am not too sure if this type of situation is claimable. For perspective, I am currently based in asia (Sin) and the insurance policies I have access to only covers missed flight situations when it is due to delayed connecting flight. My understanding is that failure to arrive on time at the airport by the passenger is a grey area at best. Were I the affected pax, I will try to reach the airport the same day if not early next day and check with the agents on site. Similarly, if a new ticket has to be bought, will try to submit an insurance claim (if purchased) citing the situation as beyond reasonable expectations.

As for OP, I admire your intentions to go the extra mile for your customers but airline rules are frequently a YMMV situation and constantly changing so planning to assist based on advice gathered today for Delta for a situation a few months in the future for xx airline may not actually be helpful and could even end up costing the very people you are trying to help. The only thing constant remains calling / turning up in person and hope for the best.