23 year old finch having trouble staying on his perch?

I have a finch that is 23 years old and he has been having trouble staying on his perch. When he falls he is usually on his back and stays like that till someone helps him back on his perch. At first he would take awhile before he acted like himself again, but I know he is old but maybe someone out there has dealt with this kind of problem and could help me. He still eats and drinks and seems like himself but the falling off the perch is the main problem.