Step 1: Feeblemind
Let’s suppose you have a way to successfully stop the creature from being killed by Feeblemind’s psychic damage, or that the creature has enough hit points to take the damage and not die, it will have Intelligence and Charisma set to 1, which can be rolled for save again every 30 days. Thus whenever the creature successfully resists, this part of the effect will be over and its ability scores should return to the original values and whenever it fails, the scores are set to 1.
Step 2: Awaken
Awaken gives the target creature intelligence 10, provided its stats are in the range for it to be affected, which is less than score 4 or to not have that score. The spell also gives the target 1 language, the ability to move and sense the world if they couldn’t beforehand, all of these previous effects are implied to be permanent. Finally, target is also automatically charmed for 30 days.
So the main idea is to exploit/avoid the restriction on Awaken possible targets, forcing our target to be inside Awaken’s range of x < 4 through Feeblemind.
Step 3: Analysis
I’ll ignore the damage aspect for Feeblemind as there way to prevent or mitigate this damage.
Both spells have Duration: Instantaneous, but part of both spells have semi-permanent and permanent effects, which are the actual effects that are clashing against each other.
Given that both spells set an ability score to a value, i’d argue you can go about interpreting the change in two ways:
- Route 1: The stronger spell wins (Feeblemind wins, as it’s a 8th
level spell vs a 5th level spell) - Route 2: The order of casting determines the final value of that ability score (Awaken wins because it was casted after Feeblemind).
- Route 3: Do either Route 1 or 2, but after 30 days, if the target fails the save for Feeblemind, Intelligence and Charisma get set to 1 again.
If we follow route 1:
Until Feeblemind is finally resisted or ended, the target will have Intelligence and Charisma scores of 1. But if somehow it was ended, then Awaken effect would kick in and make its Intelligence 10.
If we go route 2:
It would work regardless of Feeblemind remaining active forever or not (Intelligence would be 10 after Awaken, but charisma would remain 1 until the target resisted Feeblemind). I consider this to be the most probable route.
If we go route 3:
To go around this greater restoration, heal or wish would be required.
Final Considerations
Final answer is Yes, it’s possible, better with someone that can remove that Feeblemind.
However, I think we are violating the spirit of the rules here (why create a restriction that needs to be bypassed like this?).
If as a GM you’re not okay with the way these two spells can be combined, houserule that Awaken checks the original unmodified intelligence score on the creature’s sheet, not modified by anything and making it not castable on targets affected by Feeblemind.