Peace Adil,
The best rendition of the verb is determined by context. For example, please note verse 5:119, where the perfect verb is rendered in the future tense despite the fact that the same perfect verb depending on context can be used to describe a narrative in the past (2:30).
The speaker of the Quran is God and not a human. God is not subject to time and space
[1] and many narratives speak of future events if as though they have already transpired
[2]. For God who is not restricted to a past, present or future in real terms, such narratives capture the omnipresence of the Creator and evident reality of the event being narrated.
Those proficient with Quranic dialogue and the classical language in which it is transmitted find this approach quite a quintessential narrative style of the Quran in many places. Hence, good translators attempt to capture the best nuance given the context and Quranic style.
Similarly, please note the surrounding context of verse 25:30 that you have shared. The dialogue is captured in a
future context. Whether rendered to imply
'He will say' or
'He said' - the fact that the event occurs in the future does not change from the perspective of the reader who is in the present. This in my humble opinion is clear from the surrounding verses and context.
I hope that helps, God willing.
Joseph.
REFERENCES:[1] PROBLEMS WITH LOCATING GOD IN TIME, SPACE AND AS PART OF HIS CREATIONhttp://quransmessage.com/articles/timeandspace%20FM3.htm[2] MIRACLES OF THE PROPHET (pbuh) - Section "THE CASE OF THE MOON SPLITTING"http://quransmessage.com/articles/prophet's%20miracles%20FM3.htm[3] Related QM Q&Ahttp://quransmessage.com/forum/index.php?topic=408