"I was confused about how it will impact on the NHS?"
American drug companies want to increase the price of drugs in the UK as part of the UK-US trade discussions. Extra costs to the NHS will be several billions.
A fall in the value of the Pound directly impacts on the cost to the NHS of everything imported - from sticking plasters to medicines to medical equipment = more costs.
The NHS currently has 100,000 staff vacancies. 60,000 EU citizens work in the NHS. All have transferable skills and can move anywhere they want within the EU if things get too uncomfortable in the UK. In London in particular, whole hospital departments would cease to be able to operate if just half of the EU staff returned home.
Medical equipment needs to be maintained and repaired. Much of the equipment in UK hospitals comes from the EU - if it breaks down, the current situation is for spare parts to be dispatched from a central warehouse in somewhere like Amsterdam to the UK and for a UK-based technician to repair or maintain the equipment, although often these technicians also travel around Europe. If there are customs and visa delays, the equipment cannot be used, resulting in cancelled operations and patients not receiving the care that they need.
When patients are ready to leave hospital, they are often discharged to care homes or specialist care units. UK care homes are heavily dependent on EU staff. If these staff leave, the care homes cannot take the patients and the patients cannot leave the hospitals, blocking beds for the next round of patients.
Finally, the UK healthcare market is seen as a huge cherry-tree ripe for plucking by the US health companies. They don't want to take over the whole NHS - they just want to pick off the most lucrative bits and have an interest in the NHS struggling as it encourages more people to take out private medical insurance.