I Am Dealing With A 63 Year Old Mentally Retarded

I am dealing with a 63 year old Mentally Retarded man. Anything that I do to help him, HE REJECTS ! He just recently caught a COLD. SO, I have been leaving him Cold Tabs to take at bedtime. He will NOT take them. I buy him food, He will NOT eat it. I lay out a change of clothes for him, He leaves them lying and picks out his own. He was hit by a truck recently while walking on the WRONG side of the road. I told him to always face the traffic. He continues to walk on the Wrong side of the road. No matter what I or anyone else says, he IGNORES all of us....???????