Well, it is a Windows program. Dosbox is for Dos programs.
And the Android versions are not supported here. And having an iso sounds like warez to me...

If you want to run fallout 2 on win95 or 98, it should be possible in dosbox (with lots of effort, guides for creating a working win9x image, create another image for the game, having care or taking steps to not corrupt the windows image by careless shutting down dosbox - i used a ramdisk solution for win9x base images etc).

So it's a lot of work, that the dosbox devs and this forum will mostly make 0 effort to help you with (there are guides on the net but they won't help you with subtler problems, such as the shutdown thing). As there is no virtual pc for android i won't suggest it either.

BUT before you do all that, let me suggest that fallout 2 from GoG might not be the best thing to run on win95 or 98, because it's probably running the sfall fallout 2 hack, which i doubt is seriously compiled to run on those OS. in the end, although Fallout 2 is a very good game, limiting yourself to running it on dosbox 95 or 98 makes it (probably, i'm not certain) you'll not be able to get the latest fanpatch fixes (depend on sfall) and therefore be running a inferior version of the game (same thing for F1 running on DOS really).

Yes, this also annoys me. After all, i'm the kind of guy that places win3.1 and win95 games on the dosbox folder to run on a emulated OS in a ramdisk because dosbox is much more portable than wine (or 'portable' if you want to run it in a phone i guess). But for fanpatches like the ones in these games, i make a exception and play them in wine on a computer instead.

BTW, if you want a portable gaming machine and have some money to burn, the GPD Win is a x86-64 machine (intel z8700, a atom processor) and therefore windows or linux with wine will run on it (if it doesn't yet, it inevitably will).