I can tell you that the age difference between you and your former professor (40 years) is significant and might raise ethical and professional concerns, especially if he was your professor at the time he expressed his feelings for you. It is crucial to consider the power dynamics in such relationships and how they can potentially impact both parties involved.
If you feel uncomfortable or unsure about the situation, it's essential to trust your instincts and prioritize your well-being. If you are still a student at the institution where he was your professor, you may want to consider seeking advice from a counselor, advisor, or someone in authority at your school about the situation.
Inappropriate advances from a former professor can be concerning, and it's crucial to take steps to ensure your safety and well-being. If you believe you are in any danger or feel uncomfortable, consider talking to someone you trust or reaching out to the appropriate authorities for support and guidance.