There was an Old Lady...

You remember that song you learned as a kid about the old lady who swallowed a spider to catch a fly, but we never find out why she swallowed the fly? I feel like that with my cancer treatment lately. The oncologist prescribes meds to kill the cancer, and then other meds to deal with the side-effects of the cancer-killing meds, and then when those have side-effects there's still more meds to take. 

My wife is questioning my sense of humor just because I composed a little song parody. I couldn’t quite figure out how to end it though, I need some help with the last word.

I know an old man
With a cancerous brain mass
But I just can’t grasp
How he got a cancerous brain mass
Perhaps he’ll pass?

I know an old man
Who took the chemo
His White Blood Cell flow
Went frighteningly low

He took the chemo
To fix the brain mass
But I just can’t grasp
How he got a brain mass
Perhaps he’ll pass?

I know an old man
Who got shots every day,
Oy vey! Shots every day?
He got shots every day
To make the white blood cells okay.
The shots made his bones ache,
So there was still more to take!
He got shots every day
Because of the chemo,
He took the chemo,
To fix the brain mass,
But I just can’t grasp,
How he got a brain mass
Perhaps he’ll pass?

I know an old man
Who took antihistamines
Antihistamines? What’s wrong with his genes?
He took antihistamines to fix the bone ache
He got the bone ache from the shots he’d take.
He got shots every day,
Because of the chemo,
He took the chemo,
To fix the brain mass,
But I just can’t grasp,
How he got a brain mass
Perhaps he’ll pass?

Or, he’ll kick its ____