Letting Go and Letting God...

I've struggled very hard recently with turning a burden over to God. As my husband's health has deteriorated over the past year, I've seen him turn his focus inward. His life revolves around how he's feeling every moment of the day. He is constantly looking at his Oximeter to check his oxygen level and his pulse rate, even when he's not struggling. He gets out of breath easily...doing even the simplest things like walking across the floor. It hurts me to watch the decline.
Mostly, it hurts me to watch him focusing on the decline so closely. He doesn't look for things to raise his spirits, or for activities that can engage his mind, or make him smile. Instead, he sits in a chair, occasionally looking at television and every five to ten minutes checking his Oximeter.
He talks constantly about what he's feeling at the moment.
He reads his paper, while keeping his focus on that Oximeter.
He doesn't seem interested in getting cleaned up or changing clothes. And he never feels like going out of the house, though he has portable oxygen.
He's always been an active person and thrives in being in contact with other people, but now he's become a self-inflicted hermit.
I've tried talking to him, tried making suggestions, even went so far as to hide the Oximeter at one time. I've prayed with him and for him.
I don't know what else to do. I can't bear to sit and watch him, and I can't change his attitude. I've talked to God and asked for His guidance, for His intervention, and I've asked God to take over the burden. I know I have to let go and let God, but it is so difficult to know that I cannot change things, nor can I control the outcome. This is entirely in God's hands.
So, I cry, and I hide my tears, suffering in silence while my world is crashing.