In terms of the family home, does it make any difference it him that the house / mortgage is in his name as opposed to joint names? Has he more "bargaining power" in his situation?
It could, if it's an acrimonious breakdown and they can't come to an agreement - however, unless there has been extraordinarily unreasonable behaviour on the part of the wife, the difference is likely to be minimal. It may depend on what custody arrangements are being made, but without posting a great deal more information than would be appropriate, it's hard to tell.
As it stands since they are still married, under the Family Home Protection Act he cannot sell the house without his wife's consent, even if her name is not on the deeds. He will also need to ensure that his children are provided for, and will probably have to pay maintenance to the wife unless she is willing and able to go into the workforce and can earn sufficient money to maintain a reasonable lifestyle.
There's no automatic entitlement by virtue of marriage to half the house or half the net value of the house, but any settlement would be expected to make a division of assets [or possibly arrangements for future division of assets depending on where and with whom the children are to live - the fact that it's the family home is very important here] which would allow both spouses and the children a reasonable standard of accommodation.
Complicated area, and one on which they'll each need to take independent legal advice - but they're far better coming to a negotiated agreement (with the assistance of professionals) than dragging the whole lot through the courts; that's the sure-fire way for everyone to end up broke and extra miserable.