My client picked 1961 in the DateTime field

Also the date picker picked a date in 1961?? I don't imagine my client picked this so it must be an error of the form? What can I do about that?

I think your client typed 1961 in the year input guessing it was for the Birthdate. What is the date field is all about by the way? The field is a bit confusing for me. I would suggest changing the label to make its usage clear enough for your clients.