Sparkles is doomed.
The Gordon and Buchan constituency is a new one, but the areas involved are strongly Tory, the second strongest party is the SNP. The Tory candidate Harriet Cross who seems very sensible is highly likely to win according to polls. Partially thanks to Green vs SNP rivalry for the Indy vote. The fact Sparkles is standing there is not going to make the Tory vote weaker.
This is the likely result there:
https://www.electoralcalculus.co.uk/fcgi-bin/calcwork23.py?seat=Gordon%20and%20Buchan
In answer to why Sparkles is a candidate.
The Scottish Greens are very democratic Sparkles and his mates probably dominate the local group which is likely to be very small considering the area, but more to the point not many people want to stand in a seat where you are going to come 6th or 5th so quite possibly Sparkles was the only choice. Note because of the structure of the Greens it is very difficult to overrule local candidate selection unlike Labour, Tories, SNP or Lib Dems.
Sparkles might get put put on a regional list in a Scottish Parliamentary election in a few years, though I think it is unlikely, he certainly won't get the prime spots or anyway near. If you notice the Scottish Greens who actually get good positions tend to be TRA allies/spicy Straights i.e She/They or He/They types .
They are just using Sparkles as a prop. If there is actual chance for power or money their need is way bigger than Sparkles.
Nasty mumsnet cares more about you then the Greens do Sparkles.