Well I will ask you again...
What were/are your water parameters in the tanks he was housed in? What are/were your nitrates, nitrites, ammonia, and pH levels? Temperature?
It would seem to be some sort of fungus (though it may be bacterial). These diseases often come about due to poor water conditions (too much waste in the water). If one fish has it, it is likely another will, since it is water quality related, much of the time.
What makes you think your betta died of suffocation? They have fully functioning gills as well as an accessory organ that helps them breathe atmospheric air. My guess is that it was the infection that got him.
How have you been feeding your frog and what? (This may relate to it.)
As far as cleaning your tank (and I assume your glolite is still alive? - By the by, for future reference, these are schooling fish and should be kept in a minimum group of 5-6...though that won't fit in your 5g) do a large water change...say 50-60%. Take out your filter cartridge and give it a rinse in a bucket of water (the same temp as the tank, thereabouts). Add dechlor to the bucket so as not to harm the beneficial bacteria. Test the tank's nitrate/nitrite/ammonia levels. Wait a while...perhaps later tonight before bed or in the morning and do another 50% water change. Use a gravel vaccum.
If the glowlight does not make it, empty the tank, boil the gravel and decorations, scrub the tank thorougly in hot water, set it up, fishless cycle it, and try again.
EDIT: Upon rereading your original post in the other section, it would seem that you said his foot looked injured before you moved him. If so, you need to figure out the cause of that injury, to the best of your ability. Did the gourami bite at him? Did he ever get stuck to the filter? Is there something sharp in the tank, etc. Otherwise, you are likely to have a similar problem in the future.