write the script on a google doc and share it with him, make sure he has editing access. you can also use the comment sections on google docs or another platform (like discord) to collaborate and share your ideas or concepts with each other.
as for the images, have him upload them in a new folder on google drive. he can send you the link to the folder so you can see it. it will save the folder in your drive under the "shared with me" tab.
you can put the script in the same folder as the images, so you have everything together.
as someone who is also currently working on a comic series with a few others, this makes the process 100% easier.
Caption this Meme
