Withdrawal from house purchase between exchange and completion

[taffinnorfol]

My highly volatile mother-in-law finally decided to move to live near to us (her daughter and 2 x grandchildren) from a place 140 miles away where she has no friends or family and which she refers to as her prison and solitude. Yippee!
After referring lots of houses to her, she finally "quite" liked one (despite saying the kitchen's too small / her current dining table won't fit in the dining room etc.) and she put in a really low offer. The offer was, to everyone's surprise, accepted and she exchanged contracts before Christmas with Completion to take place on 8th January! It's not a dependent sale and she intended to sell her current house in the New Year.
On the last day of her Christmas stay with us, she went into a complete melt-down rant with my wife, saying that she felt forced into a decision on the house, hated it, hated us and many other very hurtful things, including to one of her grandchildren. I took her home, biting my tongue to avoid further confrontation, before New Year (as planned) and told her to let us know what she wanted us to do re the house as we were supposed to secure the property once keys were handed over. I suggested that she could sell it in Spring and, on a rising market, even make a few quid in the process. She shut the door on me! As a trained psychologist, my opinion is that she is delusional and might have a serious mental problem although I have suggested to her that the stress of the proposed move might be distorting her perception of things - that went down well!!!
The questions I have are - apart from loss of the 10% purchase price deposit, what costs is she likely to face if she pulls out from the purchase before Completion? What on earth can we do to help her see sense.

[DSJ]

I don't know the answer to your questions but I would strongly advise you to sit back & things take their course. Your mother-in-law is the only person who can decide whether to move or not. I speak from bitter experience. If she loses financially, then let it happen. Is she really the sort of person you want living close to you anyway?

[bushbaby_de]

You don't just stand to lose the deposit in these situations; the seller can sue for specific performance and force the sale, which may well happen given the state of the market now....

[taffinnorfol]

Thank you all for your thoughts and knowledge. Sadly, mother-in-law is a very difficult person who blames everyone else for her mistakes. Having isolated herself because of her moods we thought we could make her happy by including her in our life. Best intentions and all that...!!! We'll just wait to see whether she reflects on what she stands to lose in so many ways.

[ummmm]

She can be sued for a very large sum. It depends on how many are in the chain but pulling out will and can go into the 1000's on top of losing the deposit.