Is Bobbi Kristina Brown Engaged to 'Adopted Brother'?

The eyebrow-raising relationship between Whitney Houston's daughter and the man raised by the singer as a son may have gone one big, baffling step further.

Just a little over a month after Houston died, Bobbi Kristina Brown, 19, was spotted with a ring on her engagement finger following days of very public PDA with Nick Gordon.

One source tells PEOPLE, "Yes, they are engaged, but the family is trying to coax her away from it. "

Another source says, "Nick asked Krissi about a week ago to marry him" and that she's wearing a ring that once belonged to her mom. But the source doesn't know if Brown said yes.

The source does believe that Brown's grandmother, Cissy Houston, "is worried."

Brown and Gordon, 22, have been spotted getting affectionate in public recently, sharing kisses and holding hands while running errands in Atlanta.

The two have been living together in Houston's house and have known each other for years. Gordon reportedly was taken in by Houston more than a decade ago and had been living with the family in her Atlanta home.

There is no evidence, however, he was ever legally adopted by Houston, who died on Feb. 11 at age 48.

A close family friend hinted at their relationship, though, telling PEOPLE, "I have always felt there was some interest beyond a platonic interest in each other."