Which is a safe coin to invest in the long term?
How long should I hold it?
bitcoin is still an excellent belle to be used as an investment, buy now and hold for the next 6 months, I'm sure it will benefit you.
Is there a risk that I might lose it all?
the risk will always be in making an investment but that will not eliminate all assets you have
I am a noob in cryptocurrencies. Help.

I was thinking Litecoin, is it a good idea?
Litecoin is also an excellent altcoin, you can choose it to be an investment