spouse of incomplete. SCI 25 years ago. SCI aging ?

Hi heatherkford, and welcome to the forum.
I am wife to Peter who has injuries at a similar level to your husband. Does you husband walk? Peter can walk a little but gets fatigued very quickly. He is still slowly recovering after 7 years.
I sympathise with you. It is very hard to hit the right level between encouragement and nagging. As Tetra says, there isn't much you can do for someone who won't take charge of their own health. I sometimes get sick of the sound of my own voice - but unless I intervene Peter will fall back into bad ways of doing as little as he can get away with.
Maybe depression is a factor. However, I have noticed that the less Peter does, the less he feels like doing and consequently the less he is able to do. He has always been happy sitting watching sport on TV and is naturally quite lazy (he knows this about himself). He admits that often the effort involved in doing something/getting something for himself seems disproportionate to the benefit of doing it. Without my "encouragement" he would move only when he has to.
A factor for Peter is pain. Sitting for long periods means being pain free until he moves - then the pain kicks in because he is stiff. If he moves frequently the stiffness doesn't build as much so moving isn't as painful. His pain is caused mainly by spasticity and tight muscles these days and the physios pointed out to him that having your muscles "turned on" all the time is physically and mentally tiring. The physios tell him to move little and often - ideally he should get up every 20 mins minimum.
We have a white board in the hallway and he marks off every time he does a straightening exercise against the wall or walks the length of the hallway. He sets himself a target for each day and his competitiveness means he will do his best to reach the goal. I know this sounds very childish, but he finds it helps him and also he can point me in the direction of the whiteboard when I suggest he hasn't been moving much
The other strategy that helps us is selective deafness on my part when he shouts that he needs something fetching or doing - he either lets it go or comes to find me.
Of course this is all irrelevant if your husband cannot walk! But the point I am making is that it is a downward spiral - whether you have a disability or not, the less you move, the less you are able to move.
Does he have hobbies or things that stimulate him in some way? Could you build something around them? If you are not stimulated then it is easy to sleep the day away. Peter is a good sleeper too and often nods off in the afternoon if there is nothing to distract him. I am jealous as I am not a daytime sleeper no matter how tired I am.
I guess what I am saying in a very long winded way is that lack of movement and stimulation often leads to fatigue even when depression isn't present. What to do about it is an individual thing. Peter used to be a keen gardener and we have managed to find ways he can still potter around and do some pruning etc. He enjoys this and it gets him in the fresh air (though as we are in the UK it is very weather dependent!).
Re lower back pain - again depends on ability - but Peter has had some good results from laying on his bed and with my help tucking his knees into his chest and rocking side to side - this stretches and massages the lower back muscles. He does this every morning when he does his daily stretching exercises. He also has a MotoMed bike (motor assisted) that he uses every morning.
Whether it is depression or lack or exercise getting him moving again will help beat the fatigue.
I wish you luck - being supportive is a hard job sometimes.