Engaged Levi Johnston’s newest enemies - his sister and mother!

Levi Johnston has had a longstanding feud with fiancée Bristol Palin’s tough-as-nails mother, Sarah - and now he may lose the support of his own family as well. The Playgirl model’s sister, Mercede, and mother, Sherry, are furious that they were not told of his on-again engagement to the abstinence spokeswoman.

“You would think that a normal family would call you and say, ‘We’re getting married.’ We found out through the media, which is heartbreaking and rude,” Mercede tells Inside Edition on the July 15 show. After first hearing about her son’s decision to walk down the aisle in a tabloid magazine, Sherry fears she may not even be welcome at the nuptials. “I would be absolutely devastated if I wasn’t invited to the wedding – it would be the last straw. They should elope if they can’t have the Johnstons and the Palins together. But don’t leave us out of it. That would kill me,” she says.

But the Johnstons shouldn’t feel alone - former vice presidential candidate Sarah was also left out of the loop. "Bristol at 19 is now a young adult. We obviously want what's best for our children. Bristol believes in redemption and forgiveness to a degree most of us struggle to put in practice in our daily lives," Sarah and husband Todd said in a statement in response to the big news. After Levi and Bristol’s initial split in early 2009, Sarah seethed after the father of her 18-month-old grandson, Tripp, blasted the famous family to the media.