I used to be an occupational therapist, now retired. Provided that the house is warm and your folks are adequately clothed and don't wander out in the rain and get wet etc, then cold food won't hurt them, although obviously they may want hot meals. My experience of meals on wheels in London and Hampshire was that they were diabolical. In London, my mum had a carer who used to come in to get mum a hot meal. My Sis did the shopping and used to leave a list of what there was, mum would choose and the lady would heat it up in the oven or microwave depending on what it was but Wandsworth's social services are amazingly good. Keep in mind too that older folk lose taste buds and may need extra salt or seasoning in the food to get them to eat it, so cup soup not necessarily a terrible idea, although no nutrition in it. This is not me making it up, I did training with a dietician, basically and within reason, when people get older and less able to cope, the biggest thing is to keep them eating something even if the diet is less than healthy. Add in some chewable vitamins and maybe just add hot water porridge for fibre. Could your dad heat soup? The fresh ones are good, healthy and tasty and keep well in the fridge for about a week.