If you're looking for a beer that tastes on the aged side, then maybe it would be ok. The bigger beers tend to fare better with higher temperatures - the darker malts act as anti-oxidants.
I have a RIS that has been standing at around 70°F/21°C for 6 months. It's definitely changed without question - not as fresh as it was, but also still a pleasant beer since the flavors blend together better now, but one keg has definitely picked up a hint of sherry.
While the RIS will stand up to more "abuse" at higher temperatures, there is a limit, and 3-4 months at 84-88F is probably pushing it - it's the equivalent of ca. a year's aging at 70F, or 3 years at 50F.
If you have any alternative, cooler storage, I would go for that. Otherwise look for ways to reduce the time at that higher temp to the minimum.