Re-evaluating what's really important

This has been an incredibly difficult 2 weeks.  There was the lump, then the confirmation, then the treatment, and now it's the aftermath.  Leo is soldiering through, but the first shot of Vincristine took a huge toll on him (white feet, after all).
Leo has the MDR1 gene mutation. Not only does it give him incredibly adorable white feet, but it also confers sensitivity to a host of drugs - most notably, ivermectin.  But that's not all - he's also sensitive to doxorubicin (a chemo drug) and Vincristine, even stuff like loperamide (immodium!) and a host of other things.
The problem with this is that the doxorubicin sensitivity is that takes one weapon out of our arsenal. The vincristine sensitivity severely limits another one.  We have to even see if it's going to be possible to have another Vincristine treatment. Yeah, it's been pretty bad - the main symptoms are GI symptoms, and he's got 'em. He looks nauseated - licking the lips, and just that look (on THAT FACE!) where he just looks, for lack of a better work, like he's really not feeling well. He's got no energy - seriously, his walks are around the block, maybe. And his belly is unhappy. Well, it's a little past his belly...

So, Leo is incredibly good at telling you when he has to go potty. We have surmised he may have been too strongly corrected for making a mess in the house, and now he gets incredibly anxious if he's about to have an accident, and acts incredibly ashamed and demure if he does. And not in the "oh, I need to do this so I don't get in trouble" way, but hiding-in-the-corner tail-between-the-legs kind of thing. When he had giardia, he woke me up in the middle of the night (several times) and we got outside just in time. Well, last night, he didn't even have that warning, and it was a disaster. Poor boy - I kept telling him it was ok, in my best consoling/soothing voice, but at 3:30AM I was having a hard time. He then had to go out every 3 hours.

We were convinced to give him another treatment and to stay on schedule - this one is the cytocin, which he tolerates well. He still had a shoulder node that was slightly enlarged, so it was necessary to treat him. He did fine in treatment, although they called him "snappy alligator" - he was just SOOO hungry! - and then proceeded to make a mess on the floor of the waiting room while we were paying. Yikes.

So, now he's sitting here and I'm wondering how much of this is worth it? How much time are we getting, if any, and how much good time are we getting? I'd rather have a few months of EO - the naughty one that I took hiking and that jumps on the bed and does dumb things, rather than 9 months of a sick dog who's unable to much more than sit on the couch.

It's also worrying that the effects are hitting him for this long - a week later, and a for days - and this is the first treatment.  So there's some thinking that has to happen. We'll see how this goes, and when he becomes EO again.