All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
First of all, we would like to congratulate your friend on the blessing that Allaah has conferred upon him by embracing Islam. We implore Allaah to bless us all with guidance, aid, and steadfastness on the straight path until death. Verily, Allaah is near and answers our supplications.
Needless to say, lying is a serious matter; it is a grave sin and incurs the wrath of Allaah Almighty. It is unbecoming of a believer to be a liar, as the Prophet, sallallaahu ‘alayhi wa sallam, informed us. Therefore, lying is considered among the characteristics of the hypocrites as highlighted in the authentic Hadeeth. You can refer to Fatwa 88412 to learn some religious texts about lying.
Indeed, blood donation is a good deed; however, it is impermissible to resort to lying in order to carry out that good deed because there is no valid necessity for it. As long as this organization stipulates that the donor should not have been in jail or used drugs, then he (your friend) has to abide by this condition and should not lie about it. It is expected that Allaah, The Exalted, will reward your friend for his good intention and keenness to abide by the teachings of Islam.
Allaah Knows best.