Need help, feeling confused

I have a bf who is 43, 3 years ago he have a seizure 2 months another and since then he have being taking different pills, blood pressure and 3 different one 4 his seizure, now for the past 6 months I noticed we don't have much sex like we used to, acourse is not all his fault, I have being stressing too but I'm over that, my problem is that when we try to have sex his penis get hard with kissing and touching but he try to penetrate after few minutes will die, he say is the pills but I'm wonder if he is not attracted to me, I get so frustrated and mad that because I know his penis won't stay hard I don't want to have sex with him anymore, I'm like for what he is not going to finish so why even start, I even told him to try with somebody else maybe he stay hard , he say no I'm crazy but I don't know what to think anymore. Anyone know somebody who is going through something like me?????