Likes ...
ciNNamoN
LoueLLa
bEEthovEn
AvAlAnche

teRRaRium
stOrerOOm
liFtoFF
bArbArA

bIkInI
GiGGles

But Dislikes ...
CURRY
ABIGAIL
BRAHMS
ROCKSLIDE

AQUARIUM
ATTIC
SPLASHDOWN
HOLLY

WETSUIT
LAUGHS

My friend likes words that use one letter of the alphabet three times.