Mixed cellularity NH lymphoma

My brother was diagnosed with NH mixed cellularity lymphoma stage 4.  He took his first chemo yesterday.  He had to have blood and platelets today because he bottomed out already.  He has been in the hospital for two weeks receiving blood and platelets until they could find what was wrong, and they found the NH.  Any insight would be helpful.  He was so sick when he went in.  It all happened so quickly.  I am scared because he is so weak and may not be able to handle chemo.