Advise on where to find nice plus size maternity clothes?

Ok so my sister is TTC. She wears a 3x currently which I’ve been able with a lot of mall hours building arm strength learning to use a wheelchair since I developed a neurological disorder that looks like a mix between seizures (neg eeg even during convulsions) and dystonia which forced me from super active to full time wheelchair user find some nice flattering outfits. Most stores stop carrying anything short of circus tents over 3x. She already struggles with self esteem and feeling like she’s unattractive so I like to spoil her with nice flattering outfits cause she works 12 hour days and doesn’t have time to shop for anything besides essentials. She has advanced endometrial hyperplasia too. They are still trying to thin it enough to even start IVF and as soon as she’s recovered from delivery she must have a hysterectomy or they have said basically she WILL for sure develop cancer within a year. Maybe I’m compensating cause I’m worried I’m gonna lose my baby sister as she TTC but I want to get her some awesome flattering maternity wear if the pregnancy takes, which isn’t too hard in the early months, but later the only stuff I’ve found for over 3x maternity wear are hideous circus tents and I know that will make her self esteem even worse. Can any of you lovely ladies offer advise on where to find some nice larger maternity wear for her? I want to spoil my little sis.