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 is His slave and Messenger.
Following the sequence (of alternatives) when making the expiation for Thihaar (the saying of the husband to his wife "You are like my mother to me", i.e. "You are sexually impermissible for me exactly like my mother") is an obligation, so it is not valid or acceptable to move to the option of feeding (of poor people) unless one is not able to fast as we clarified in Fatwa 88080 and 85975.
Therefore, your friend should fear Allaah and be patient and expiate as Allaah ordered him to expiate. Just considering that fasting is difficult is not a sound reason for moving to the option of feeding unless he has a valid reason for doing so. Similarly, just having the money does not make it permissible for him to move to feeding.
Had your friend feared Allaah, he would not have committed this sin and caused himself this embarrassment, as he could have avoided this. Indeed, there are peaceful means to solve marital problems other than Thihaar, so we advise all the Muslims to be careful and cautious in this regard.
Allaah Knows best.