((A LOT OF SPOILERS))
1.
Yes, his mom is going to be alright he is going to use the water (don't remember the name ) he crafted to wake her up .
2.
I'm not totally sure but for the little I know "the strongest hunter in the world " (Probably he is just going to take the title at the end of the Manga ?)
3.
In jeju island he(mc) will fight the "Ant king" and turn it in a shadow , his name will be "beru" (if I remember there's a joke behind it ?) and beru will be able to communicate with mc.
4.
There's a chance that when the other shadows of mc reach a certain grade they will be able to talk . (But I'm not so sure bc there's a certain arch where's beru did eat some Japanese corpses or people to be able to learn how to talk japanese, but beru is kinda an exception.....)

.. I'm in the hospital getting life support. BECAUSE MY HEART CANT TAKE IT.
Is his mom gonna be aight? How much stronger does he get? Will his shadows learn how to talk to him? Funny conversations with iron and all of them?
Σ(  ̄□ ̄||)