I Am A Caregiver For A Man Of 43, Who

I am a caregiver for a man of 43, who 9 yrs ago suffered an AVM. The medications he currently takes are as follows: amantadine 100mg (1); CITALOPRAM 30mg (1.5); gabapentin 300mg (4); lamictal 150 mg (2); phenobarbital 32.4 mg (4); sulfamethoxazole ?mg (1);. his questions is: would any of these, by themselves or taken together cause his penis to shrink. He is impotent now, but has not always been since the AVM. He is married, lives at home, but his wife is not encouraging in any way. He is not trying to change what is, but just wants to know if the shrinkage is a reality. Thank you.