Krishna, first let me say how sorry I am about your Dad. Also please forgive me for trying to play Doctor here but I just wanted to awnser you to maybe give you some info and I hope it is not incorrect.
You mention swelling and the (anti-biotic Decdan)
----could this possibly be a steroid called I believe Decadron.
As for the chemo Methotrexate I believe I had that for my Leukemia treatment. It is used in the "Maintenance" phase of treatment and if memory serves me correctly it is in pill form. I handled it very well and did not get sick from it.
I hope I have been some help to you and keep in touch and let us know how you are doing.
Always,
Mark