Will a person suffering from magic and obsessive-compulsive disorder be held accountable for misunderstanding a greengrocer’s words (thinking he said "Lot" instead of "nuts")? Is that considered disbelief? Will he also be held accountable for imagining obsessive matters while visiting the tomb of the Prophet, peace and blessings be upon him? Is that considered disbelief?

We ask Allah to remove the whispers (waswas) and the effects of magic from you. We advise you to abandon these whispers and strive to get rid of them. What you mentioned does not contain any mockery of the Prophet Lut (peace be upon him). If a person who is not a prophet is named after a prophet, it is permissible to use the diminutive form of the name. Ibn Hajar says: "The names of the prophets are glorified when they are accompanied by something indicating that they refer to a prophet. However, the name alone does not fall under this ruling." The disbelief you mentioned has not occurred, nor has what you imagined about falling in front of the grave for fear of being killed, which does not constitute disbelief. Divert your mind from this matter, beware of isolation, seek righteous company, and do not despair in seeking a cure for these whispers.