Since you say it's superstition, it's definitely not good; But since the old man is superstitious, of course he won't listen.
If you are religious, you can find a believer to enlighten him; If there is no basis for believing in ghosts and gods ... it's hard to say; However, the old people are usually lonely, in need of comfort and pitiful. If there is no harm to yourself, your family and society, believe it; It's also my fault that my children don't care enough about the elderly and don't find correct beliefs for them.