Just resat (as took too long to do finish practical side due to long gaps because of work/weather).
There is a whizz wheel app "Flight Computer" that includes clear instructions for using it in the paid version - no connection other than user for practice.
There were also distance/time/speed causation and conversions between NM, statue Mile and kilometre and kg, lb gallon density calculations - which seemed to be there to check the units as well as calculation asthe wrong answers included the correct number with wrong units and correct units with wrong number
Pen and rough paper definitely allowed and I drew out anything that involved a calculation at all in any paper.
E.g. (W-E+)CDMVT(W+E-), wind triangles, course correction, altitude v height v MSL on QFE or QNH, ETA based on course covered etc. There were performance tables where figure expected was half way interpolation so again rough paper very useful.
Any set of practice MCQs would be useful I used airquzz last time and this time ones included in course.
There are approved scientific calculators (sorry not sure of list) but it does not include a iPad or iPhone (or android) so although they were all I used for practice papers I had to borrow a legal one for the exam and use the physical whizz wheel.
Good luck to your partner