Everyone has a different definition of and differing standards for what constitutes a "friend" but there's some things I feel like should just be the basic standard. One of those things is taking interest in the major interest of a loved one even if you don't personally enjoy that hobby on its own, because it should be personal. You love the individual, whatever is their passion is their passion and it's an integral part of them, either for now, or forever.
I always invest in the most beloved interests of those I care about even though 99% of the time I would never care about said interests from anyone else. It find a way to enjoy those interests through my friends or family. I ask questions. I learn about their interest.
People put way too much importance on having to naturally have common interests--the moment those common interests change, since people change and so do their interests, what happens with the friendship then? I don't subscribe to sunk costs and all but it seems silly that some relationships can fall apart because people just don't know how to invest in each other's most important interests (if you know said loved one doesn't mind you taking interest, and wants to share, as opposed to those who want their close ones to stay out of their personal interests).
Now, with that said, there are some interests one may never be able to take interest in, perhaps due to money costs, or logistical reasons, or time constraints, or crossing barriers one just cannot in good conscience cross and things like that.
In all fairness, reading is a huge time investment. But I also think it'd be simple to just say to one's friend upfront, "Hey, it usually takes me a long time to read and all and I rarely ever get around to it. I can probably only read a couple chapters because I'd like to get a sense of what you work on but I don't really have the time or attention span to be a long-term reader." Or anything similar. Communication is key, and ghosting something someone has sent you, if you okayed it, is plain rude and way more damaging than the risk of mentioning that to a writer.
Even if you do okay it, you can always back out of it, because consent can be taken back. "I was really worried about hurting your feelings when I said okay, it caught me off guard, but I gave it some thought and I realized I can't commit to this." That'd be great. Totally normal and reasonable.
OoOOooh I can't stand this
. I know there's a balance: time off from work shouldn't be assumed to be "freetime" because everyone needs "me time", where they do what they want and they don't always have to be thinking about commitments to others and keeping people happy and all. But when this happens on a consistent basis it moves beyond "me time", it's just plain not respecting a part of your friends. Currently going through this with a friend who invited me out somewhere very last-second then...forgot she made the plan. And I was left completely hanging. Twice. One instance in which it turned out she decided to party all night somewhere, and she knows how hard it is for me to go out with people; I'm a house hermit, I don't like the outside unless it's just me in nature, and when things are last-minute it gives me anxiety but I love her so I agreed. And oh my goodness she couldn't even remember.

That made me laugh 

Congratulations! That's such a huge step. It also looks like you have quite a few stories and episodes up, so that's even more amazing
Yayyyy!