Man proposes to girlfriend & her sister with Down syndrome

Two sisters from Santa Claus, Indiana are preparing for a very special day this fall.

Ashley Schaus, 23, met her fiance, Will Seaton, in 2010 after they both attended a car show. Not long after they started dating, Ashley introduced Will to her sister, Hannah, and told him they were a package deal.

"She has Down syndrome and diabetes, and I look after her and protect her," Ashley told FOX 5's Katie Muse. "To be with me, you must accept her and love her as well."

Ashley said Will went above and beyond to do just that, and has treated Hannah like a little sister from day one.

The Schaus sisters have been inseparable since the day Hannah was born. From running errands, to school visits and even sleepovers, they do just about everything together.

"Hannah and I share a very special bond," Ashley said. "We built our home close to Hannah, so that we can spend a lot of time with her while still having our own privacy."

On March 8, 2016, Will decided to pop the question and asked Ashley to marry him in a field of spring flowers near their home. However, Ashley wasn't the only person who Will proposed to that day.

"Before you knew it, he was down on one knee, asking her [Hannah] to be his best friend forever," Ashley said. "It was the sweetest moment in my whole life watching Hannah be so happy and feeling so special."

Ashley said after Hannah's initial reaction of being surprised and happy, her sister then cried.

"We may not know what the future will hold for Hannah, and I hope that someday she finds a sweet boy, but for now, I am so thankful she got to enjoy that moment that every girl dreams about," Ashley said.

Will and Ashley will tie the knot on October 7 in Rockport, Indiana, with Hannah right by their side.

"She's more than just a bridesmaid, she's practically one-third of the wedding," Ashley told FOX 5. "Hannah is going to be the 'best sister.'"

According to Ashley, her sister will share vows with Will during the wedding ceremony.

"They will make promises to each other to always care for one another, share secrets, make jokes and go fishing, as that's one of their favorite things to do together," Ashley said. "Will and I will share our vows and we all three will walk out down the aisle together."

In addition to the vows, Will and Hannah will also share a first dance to Harry Nilsson's "Best Friend."

"She will be a part of everything when it comes to the wedding."

Ashley said Hannah, 15, is on cloud nine and has enjoyed the attention of being the "best sister."

"When Hannah was born and they told me I had a sister, I never would've thought that I would've shared my wedding day, my engagement, and my whole life with her, but now, under all the circumstances, I wouldn't have it any other way," Ashley said. "I want Hannah right by my side throughout everything and someday in the future, whenever Will and I start a family, I know that Hannah will be a big part of helping raise our child. She will be a great aunt."

Engagement photos courtesy of Bret + Brandie Photography