Michelle, it can be very difficult to come to terms with life as it faces us. It is impossible to read your words without being deeply affected by them.
I have worked in both neonatal and paediatric intensive care units and working in those places one can feel a pall of sadness is ever present. Young lives are frequently lost and trying to help bereft parents through that dreadful time is one of the most difficult jobs I have ever experienced. I could not manage more than 2 years of that work and I felt a complete failure because of my own distress and having to leave that work to others.
Time passed and I moved to other areas of work and I came to realise that sadness is a integral part of every life. I found that when people were near to the end of their days, often in pain both physically and mentally, all they seemed to require was to know that loved ones were near and that they were not going to be left to face their final mortal moments on their own.
You do not need any special training to hold a hand while listening to someone who is weak and unwell. Talking to them, reading to them, propping them up with pillows, keeping them warm (or cool) and generally attending to their comfort. Simple measures, like a fan, can help if the person feels too warm. If they are unable to drink, the touch of ice cubes on the lips will keep them moist and stop them from cracking and help the person to feel refreshed.
The constipation can be a problem and glycerine suppositories and prune juice have already been mentioned. It is often difficult getting a very weak person to the bathroom. If you think it possible to manage, you could consider a commode chair (toilet seat on a wheeled frame) that will fit over the toilet. I would consider using the standard intensive care method; which is to cover the bed with absorbent paper sheets that are plastic backed on the side that goes towards the bed. It is a lot less distressing than trying to move a person to the toilet whenever they feel the need to go.
Respiratory distress can be helped by positioning a person with pillows so that they are sitting at about a 45 degree angle from the waist up. A folding bed table can give additional support for the person to lean on. If you choose to use this method, ensure that the hard edges of the table are adequately padded (use a couple of small soft pillows placed under the arms), to help prevent pressure sores.
Weight loss and laying in one position can produce pressure sores that are uncomfortable and can break down leaving a wound that is a portal for infection. Frequent position changes (side to side) will help to prevent this. Very weak, undernourished people will often need positional changes every 30 minutes within a 24 hour period.
The subject of oxygen being used to assist respiratory distress is often raised. As the saturation of oxygen drops within the cells, because the respiration power is shallow and the total volume of the lungs is not being filled, the cells get less oxygen. This can cause confusional states and these are not helpful. Oxygen is able to supplement what a person is taking in via their own breathing effort. Used as a medical gas, oxygen is of great benefit. Be aware that it poses a fire hazard. Good medical advice is an essential part of good oxygen therapy.
Consider sedatives. Most people will not want to drug a person into insensibility during their final days. Sometimes a person will be so distressed by their discomfort, that sedation will be a blessed option. I doubt the ability of most general doctors to prescribe the most suitable product, in the right frequency and at the right amount, and if you have any sort of hospice near to where you live, or available by phone, you may be able to get some really expert advice on sedation.
My heart goes out to you and your family, Michelle. The few simple measures outlined above are all that will you need to do for your very own hero. Being there and caring about our loved ones is all that is within our power. It is always preferable that the relatives and friends care for a person, instead of having people we do not know, working in institutions that will have a different agenda to ourselves, and who do not know our loved ones. It is clear that medical professionals (with their special view of of illness) frequently gets in the way of letting families do whatever would come naturally to them; if they were left to their own devices.
also Jeff