93 yr old male swollen lft hand contuinous for three weeks or more. Have put hand in sling and iced swelling reduces but he refuses to do for any helpful length of time, and will not get treatment my brother and I are at an impasse please help.

First. First even if you can't find out right away what is causing the swelling, having it a sling is probably not helping a sling keeps the hand dependent and below heart level thus increasing swelling. Even if you raise the hand up in the sling then your elbow is flexed also impairing drainage. Its best to elevate the hand on pillows on your chest or abdomen while lying down or try to keep you fingers pointed to the ceiling. Do not put your hand over your head while sleeping next motion, making a full fist and fully owning the hand helps prevent swelling and congestion. Ice is good for swelling but one must be carefu with ice in vascular insufficiency problems or after vascular repair.
You. You can lead a horse to water.... Unfortunately, you cannot force him to do anything. The important question is whether he has any circulation problems. Sometimes swelling is from a clogged vein. A clot in the arm is less serious than in the legs, but can be a marker for larger clots elsewhere. The next question is whether he has an injury. If he is going about his daily activities and does not have discoloration and pain, then the swelling is not as important. Don't turn it into a battle if it's not limiting his function.