First of all, sorry for the loss of your husband. Thank goodness you and your passenger are OK.
If I recall correctly, the rear brakes on the accord of that year are drum brakes. Either the brake line or the wheel cylinder are leaking. Once you find that out, determine what part to replace and then do a complete bleed of the system. Also, given you have had one failure, I would give the whole rear brake system a once over to see if anything else need replacing.
Good ETCG video on drum brakes: