There is now very little doubt that if we remain in the EU then the NHS as we know it will eventually cease to exist.
Also, if we remain in the EU, with no control over who enters our country, before it ceases to exist in it's present form it will become increasingly under pressure and unable to cope with demand.
The timescale for these two eventualities is impossible to ascertain, but we know that in Germany for example, the millions of migrants that Merkel is intent on letting in will be given EU passports if they stay, and will therefore be able to move to any part of the EU that they choose.
The same will apply to the millions of Turkish citizens who Cameron is so keen to let in to the EU despite what he is now saying. A few months ago he was telling the Turks that he was their greatest ally and was intent on fast-tracking their accession to the EU, now he is assuring the British public that it will be the year 3000 before they join; he will just say whatever suits his agenda at any given time.
The recent migrant deal the EU struck with Turkey is about to go tits up as Erdogan has sacked the man who did the deal and has taken control. Erdogan doesn't mess about and will be aiming for a far better deal; the EU, in the face of the migrant crisis, will find it difficult to say no to his demands.
So although we don't know exactly when it's going to happen we do know that the pressure on an underfunded NHS will increase if we stay in the EU, and also we know that it will eventually be sold off after TTIP is ratified.
If we vote out then we will immediately retake control of our borders and start restricting immigration numbers to a realistic level. The pressure on the NHS and other benefits systems will lessen, and additional money will be available to improve these services. Nobody knows the exact figures, but we do know that millions of pounds are transferred to the EU every week - this fact has never been disputed, the debates always end up in petty squabbles over the exact amount, how much we get back as a rebate etc, but these things don't make much difference, the fact is that millions of pounds that now leave our country every week will stay in this country if we vote to leave.
The other thing that we know for sure if we do leave the EU is that we will not have an unelected committee of faceless American and European corporate fat cats selling off our NHS.
If privatisation of the NHS does come up the British public will be in a position to vote against such a move whereas if we stay in we will not.