Is there a standard approach for grading sequence-based questions?
You could give points for the longest subsequence in the correct order.
Alternatively, you could make it an open question: "Describe the process step by step, make sure to include in your answer 1, 2, 3, 4 and 5." Then grade by a few essential insights that need to be in the answer. This eliminates any easy guessing and shows you why the student misorders the process.
Also a possibility is to only let the students place 1 element of the process in the correct spot. For example:

Where in the process does 1 happen?
A. before 2
B. after 2, but before 3
C. after 3, but before 4
D. after 4, but before 5
E. after 5


Another possibility is to focus on the parts of the process that directly follow each other. Suppose the student answered "1,2,3,4,5", you could look at the pairs (1,2), (2,3), (3,4) and (4,5). Then give a point for (1,2) if 1 directly precedes 2 in the correct sequence, give a point for (2,3) if 2 directly precedes 3 in the correct sequence etc.