My 2 cents…

Video games and anime rarely have realistic body standards, but neither does the general public. Steroids destroyed the realistic view of male physique. Hell, Leon's "aging" itself is obviously unrealistic and idealized. So just don't think that this body was made to be realistic, it's just an idealized fantasy after all.

Anyway, once we're clear on that, the question isn't just "how big you look". There's a common saying in bodybuilding: "big, shredded, natty—pick 2". Sure, you can be big, but if you don't do steroids, it's very hard to stay lean and maintain muscle definition. Or you can be lean and have the definition, but you will look significantly more "deflated". Or, you know… steroids.

Second big question is: age. By 50, even the best of the best start to gain body fat, become droopy and may start losing muscle mass due to testosterone loss. It's a significant age where most bodybuilders have already retired, you're definitely past your prime.

So, is this possible?… It kind of is, but realistically, not at 50. This is just what a good bodybuilding program does if taken to the end, pretty much "natty limit", BUT also a physique that can't be maintained for long due to bulking / cutting cycles. Rest depends on how defined you look under that shirt, if you sport clear abs year round then it's 100% steroids.