Buddhism (, US: ) is the world's fourth-largest religion with over 520 million followers, or over 7% of the global population, known as Buddhists.Buddhism encompasses a variety of traditions, beliefs and spiritual practices largely based on original teachings attributed to the Buddha and resulting interpreted philosophies. It originated in ancient India as a Sramana tradition sometime between the 6th and 4th centuries BCE, spreading through much of Asia. Two major extant branches of Buddhism are generally recognized by scholars: Theravāda (Pali: "The School of the Elders") and Mahāyāna (Sanskrit: "The Great Vehicle").
It's greatly noble that they are very good people, and for sure their nurturing contributed to your personality as well.
As you know, religion and becoming religious is a choice that must come from within. Even as Muslims, we always pray to Almighty God to keep us "guided" on the right path. Hidayah, or guidance is in the hands of the Almighty. If your grandparents, or anyone else around you has a potential that Allah ta'ala sees in them, then they will be guided to the light of Iman. If they do not "convert" to Islam, it does not mean they are evil, but just that hidayah is with the Almighty.
The best thing you can do is set yourself with high standards in your conduct, in your ambitions in life, and show those around you how a true Muslim should be.
That itself is a great form of conveying the message of Islam, and then it is up to them to investigate, or ask questions, and so on.
If you see that your grandparents are interested, or have questions, discuss what you know with them. However, never allow it to become an argument, or upset them, as they are your grandparents.
In any case, always do dua for yourself, your parents, your grandparents, your siblings and everyone else, that God showers them with His compassion and Mercy. Ask the Almighty to enlighten your hearts, and ask Him for guidance.
You can also do tawassul to Ahlul Bayt (a.s.), to give you the strength you need, and introduce them to Ahlul Bayt (a.s.), in a positive manner. You dont know what the outcome will be, but at least they will think positive of your religion, and understand you more.
With prayers for your success.
In the name of Allah
Their permission is not needed in this case.
However, it behoves a Muslim to be respectful towards the parents. So try to get them on board if possible.
Greed is described by the Holy Prophet (peace be upon him and his family) and the imams (peace be upon them) as a disgrace, like mentioned in the narration of Imam al-Baqir (a.s.): 'There is no disgrace worse than that of greed.’[Tuhaf al-’Uqul, no. 286]. Imam al-Hadi (a.s.) described it as ‘an evil characteristic.’[al-Durra al-Bahira, p. 42], and the Prophet (s) furthermore concluded that ‘Greed takes away wisdom from the hearts of the knowledgeable men.’[Kanz al-’Ummal, no. 7576].
It is described as a form of poverty because you are never satisfied with what you have: The Prophet (S) said, ‘Beware of greed for it is ready poverty.’[Kanz al-’Ummal, no. 8852], and a form of slavery because you are a slave to your lower self and its desires: Imam Ali (a.s.) said, ‘Greed is an eternal slavery.’[Nahjul Balaghah, Saying 180].
Imam Ali (a.s.) said, ‘The servant of Allah is free so far as he remains content. The free man is a slave as long as he is greedy.’[Ghurar al-Hikam, no. 413]
Imam al-Hasan (a.s.), when his father asked him about greed, said, ‘[It is] when you count what is in your hands as a source of honour, while you count what you have given away as a waste.’[Bihar al- Anwar, v. 73, p. 305, no. 23]
A greedy person is a person who cannot be satisfied and won’t look at all the blessing bestowed upon him. That is why he’s always in a state of poverty because he can’t make use of what he already has, as he is always looking for more, Imam al-Sadiq (a.s.) said, ‘Greed is worse than miserliness because a miser is parsimonious in spending what he has, whilst a greedy man covets that which others possess in addition to what he himself possesses, such that whatever he sees in the hands of others he wishes to be his – lawfully or unlawfully. He cannot be satiated, and nor does he derive any benefit from what Allah has granted him.’[Tuhaf al-’Uqul, no. 371, 372].
In reality it is a neglecting of your soul, and despite the greedy person thinks he “deserves” more, and that is the reason why he always wants more, he is neglecting his true being. Imam Ali (a.s.) said, ‘The person most neglectful of his own soul is the one who is full of greed.’[Sharh Nahjul Balaghah li Ibn Abi al-Hadid, v. 18, p. 84]
So where does greed comes from? Imam Ali (a.s.) wrote in his letter to al-Ashtar when he appointed him governor of Egypt, ‘Verily miserliness, cowardice and greed are all evil impulses brought together by entertaining a low opinion of Allah.’[Nahjul Balaghah, Letter 53], he further explained that ‘Cowardice, greed, and miserliness are vile traits that come together as a result of distrust in Allah.’[Ghurar al-Hikam, no. 1837].
Luqman (a.s.) said to his son, exhorting him, ‘If you want to attract Honor in this world, then cut off your greed of drawing advantage from what other people have in their possession; for verily the prophets and the veracious ones achieved what they did by cutting off their greed.’[Qasas al-Anbiya’, p. 195, p. ].