Hi jonah
Just to say it's good that they are keeping such a close eye on your brother with regards to his blood tests. Try not to be too worried, my husband will go for bloods taken on a morning and by tea time they are ringing about the results, usually to tell him to stop taking such and such tablets.
I know it's not the same situation but they can do them quite quickly as a matter of course not neccessarily because anything is terribly wrong so please try not to worry yourself too much.
Please keep us informed of how your brother gets on. All the best xx