all i can do is share my experiences on this.
i have very hbp and take meds for it. have been on them for some time now and it still runs high.
i go on all the rides, coasters and anything in the park.
i just ignore the signs that warn against going on them..........lol
i don't have any bad medical reactions to going on the rides.
as long as i don't miss a dose each morning, i am fine.
this is something that i can't answer for you but something you two and the doctor should discuss. all i can share is i have not had any bad effects from going on the rides.
some doctors advise against certain rides, some don't.
if he would go on a ride that has a warning and gets light headed or has that extra heart beat while on it, then that would be the time to take a break from the thrill rides.