Recommend healthy frozen meals for 80+ uncle with kidney stones!

[BaleOfHay]

I know, niche. My uncle is 84, active, non cook. He has recurrent kidney stones and we think his diet isn't helping. He's not going to start cooking now. Can anyone recommend any frozen meal deliveries that might improve his diet?

Wiltshire farm food aren't cheap but are aimed at people who don't/can't cook.

Are they healthy though? He uses ready meals form M&S a the moment, but we think they are contributing to his kidney stones