Does anyone have any advice on how to handle criticism of their performances?

I am learning storytelling and have been telling for two years come this summer. I am being supported by a master storyteller who is an old friend, and am also hoping to be mentored by another master storyteller (once funds are available). Currently I am busy going to a good assortment of workshops/masterclasses to learn and improve skills. I get good feedback and encouragement from the professional storytellers.

I try out some of my material at local folk clubs. I have one gentleman who insists on criticising my performances. I believe he likes my singing voice.   However, he has never, ever had a good word to say about my storytelling. He is an experienced performer, but an amateur not professional, and is a singer, not a storyteller. I find this gentleman very offputting and because he has no experience in storytelling some of his advice is not accurate.

This gentleman can be kind and helpful, and I do think he believes he is being helpful by giving me advice based on his long experience performing. In fact he is very offputting. Does anyone have any tactful comments that I could use to ask him to refrain from negative criticism? Although experienced he is not a perfect performer by any means - he frequently forgets his words.