Responses
Probably not it but its sounds little similar to https://www.mangago.me/read-manga/the_sacred_serpent_s_seduction/
Its his grandpa though and i didnt finish it so im not sure...
It's this one tysm
BL, mc is living in a village with his grandma and goes to the mountain to meet ml, the mountain god, then returns but forgets about it. Also I think his grandma died at some point. Sadly I don't remember anything else. I think all the above happened in dreams but I might be mixing up different stories there