Ends of most leaves curling, turning yellow, few buds have damage on pistils

[Dr.Dankmen]

An aqcuatance of mine has eight bubba kush growing in russia. he said its indoors and grown with a soil sand mix and under neath a thousand watt light with a little more than two feet between the top of the plants and the light, the plants themselves are about a month or so into flowering and the buds are starting to conect on the colas, according to Gustav. His internet is shot and he wanted me to ask what could be the cause of many leaves curling downwards and yellowing at the tip. as well as some, not many, buds that have some apparent rot on some parts of the pistils. also looks like it might only be rotting on buds that have a leaf growing right above it and is kinda resting or rubbing ontop of the pistils. also leaves seem kinda more veigny then normal. any possible diagnoses