I am 65,can an employer demote your position because they think it would be easier on you?

I was hired as an electrician 1 year and 3 months ago. I have no bad points on my record. I am retired from a school district as their lead IT man, I am 65 years old. (It has been hard to find a job at all at my age, even though it is illegal to not hire someone because of their age.) I was sick with bronchitis and was out a few days using my sick days. I came back to work and the lead electrition quit. So my boss put me from electrician to maintenance. My boss said it would be easier on me. What does easier on me mean? I did my job well and the lead electrician couldn't have done of the jobs he had done without my knowledge. They moved a man from another area to the lead electrician position, he was moved because he was accused of sexual harassment at his other location. He was not an electrician at his other location. I was hired for the electrician job and I feel I was moved due to age. I have no corrective action on my record and I have always done great work.