My laptop runs rather slowly and I want to play on my father's PC MC Java Edition, but is he afraid of a virus because there's important data on the PC?
Let's put it this way: If you don't get it on sites like "Minecraft Free 100% No Virus" then nothing will happen.
Go to minecraft.net and buy / download the game there.
The site is trustworthy and direct from Mojang or Microsoft
No, as long as it stays with Minecraft. But don't download mods / shaders / texture packs for safety
The game itself is the virus.
Respectively. Get all content only on Curse (indirectly Amazon).