Was I Wrong for Advising My Uncle About Shrine Practices?

Assalamu alaikum, dear brothers and sisters. I need your advice on something that happened recently with my paternal uncle (my chachu), who is in his early 40s. We had a discussion about the concept of darbars/shrines in Pakistan and what Muslims should or shouldn't do at them. During our talk, I questioned the darbar system. I said something like: if visiting a particular shrine is considered so important, then why don’t we create a similar 'project' around the Prophet ﷺ? My intention was not to disrespect the Prophet ﷺ at all-I was just trying to understand whether these practices have a basis in Islam. My uncle then compared it to the Prophet’s ﷺ resting place in Madinah, saying it is also somewhat like a darbar. I explained that I don’t think the two are the same. At Masjid an-Nabawi, the blessed chamber is enclosed and protected, and visitors stand at a distance to send salam. They are not there because the enclosure itself has some independent power or because they are seeking something from the physical structure. I was talking to my uncle calmly, even smiling. I wasn’t shouting or trying to insult him. My intention was genuinely to explain what I believe is the correct Islamic position and to advise him respectfully. However, during the discussion, he became angry and called me "parhe likhe jahil" (an educated ignorant person) and then got up and walked away angrily. I want to clarify that I was not being aggressive, angry, or confrontational. I was actually smiling while talking to him and was trying to explain my point calmly and respectfully. I wasn’t raising my voice, insulting him, or trying to make him feel inferior because of his age. My intention was genuinely to guide him and share what I understood to be the correct Islamic position. Now I’m wondering: - In Islam, is it permissible/recommended for a Muslim to advise another Muslim when they believe that person is following an incorrect practice or understanding? - If my intention was genuinely to guide him and I spoke politely, would I receive reward for giving naseehah even if he didn’t accept what I said? 🥺 - Did I do something wrong simply because I was advising someone older than me? - How should I have handled the conversation once it became an argument? I’m specifically looking for an Islamic perspective based on Qur’an, authentic Sunnah, and scholarly understanding, not just opinions about family arguments.