i STRONGLY recommend this:
the smartest thing she can do is go to a tailor and have her clothes made. it is because plus-size clothes tend to not foresee the HEIGHT of plus-size women. usually ok ang fir horizontally pero vertically hindi maganda ang fit.
she can always naman refer to magazines and askthe tailor ano ang magandang fabric. also, pwede rin siya magapagaya. she can borrow clothes as samples from friends/relatives and ask the tailor to copy.