Free hospital treatment?

Hi guys, this may have been covered (if so, i'm sorry, but can't find anything) i've googled it,but it's all confusing.

1) It's nearly time for us to move to malta & renting. I know i can stay there for 6 months before claiming residency, but do this mean i can claim free nhs hospital treatment if needed for those 6 months.

2) When i claim residency, would i still be able to claim free nhs treatment or have to pay NI to someone? and if so how do i go about it as we work from our computers and how much.

3) The reason i'm asking this is i need B12 injections every 12 weeks by hospital nurse & i may have the start of Scleroderma/lupus which may need further hospital appointments/treatment.
I have celiac glutenfree food on prescription, folic acid tabs & a on going antibiotics for Rosacea, i will have no trouble buying these on line, but worried about my B12 injections?

I would love some information asap please so i can get sorted in some way, just scared silly lol as it's a big step in our lives. Thank you everyone for all your help and advice in advance.