Caridina shrimp, my advice is get some water test strips and get your ph and kh as low as possible with a gh below 10 (water changes with store bought distilled water is good). Would recommend buying a TDS meter, getting that around 130 (higher is okay) is your best range for molting
It’s a female neocardina shrimp (most probably a cherry if it is red in colour; can’t really make out whether red or brown in pic. If brown, it maybe the chocolate variety). Like others said, don’t get a betta if you don’t want to risk getting this killed. Neos are fairly hardy otherwise. You can any nano fish species that you like. And very sorry for your loss. Your brother would appreciate your sincere attempt in keeping his legacy alive.
Wattled_crane 
Some of my oldest neo reds, have this similar streak down their back before molting…
Caridina shrimp, my advice is get some water test strips and get your ph and kh as low as possible with a gh below 10 (water changes with store bought distilled water is good). Would recommend buying a TDS meter, getting that around 130 (higher is okay) is your best range for molting
Neocaridina I think. As soon as the betta tastes one, it’s over for all of them. Just a matter of time.
It’s a female neocardina shrimp (most probably a cherry if it is red in colour; can’t really make out whether red or brown in pic. If brown, it maybe the chocolate variety). Like others said, don’t get a betta if you don’t want to risk getting this killed. Neos are fairly hardy otherwise. You can any nano fish species that you like. And very sorry for your loss. Your brother would appreciate your sincere attempt in keeping his legacy alive.
Does anyone happen to know or verify if this is a cherry shrimp? If not, any ideas what else it could be?
No problem, good luck!
Maybe a red cherry shrimp? Im not too sure though im fairly new to shrimps, but i know sometimes they can have red stripes down their backs