Its could be a subjective question, so I will answer from my view.
As he is a student in UK, living there, and probably wants all the postal communication to be delivered at UK address, it might be safely assumed for this above-said purpose that his residence/current-permanent address is UK one.
Now, residence word has multiple meanings as per context.
In immigration, it might mean certain fixed number of days which qualify you resident or not. Like, you can not apply for Schengen visa from Qatar as non-Qatari, if you are in country for less than 90 days, or you are on tourist visa, because both these disqualify you from being resident of Qatar.
For tax purposes, you are indian resident, and thus are supposed to pay tax on your worldwide income to India, if you are in India for at least 182 days of that financial year.
For certain immigration to UK as EU resident, you are supposed to be living in EU for 6 months and should be working or studying.
As he is going for tourism to India, and his "present" centre of living is in UK (studying, spending most of the year), he might consider putting UK address as both present and permanent address. Note that it is permanent as of now, tomorrow or after 6 months, or 6 years he might move places, and thus permanent address is not permanent-for-life.