Can sole physical custody be changed to shared custody?

Custodial parent(the mother) was recently been granted sole physical custody even though they already had it, but now it is documented in the courts.The noncustodial parent will have visitation 6 hrs a week.Can the noncustodial have the sole custody changed just because they want to? The parent with the sole physical custody is doing a great job with their child and is very stable financially,mentally and physically.The noncustodial is going through constant financial problems,facing foreclosue,3rd wife,three kids by three different partners and has to pay child support for two of those children and has stated in the past that they would move out of the country because of having to pay child support.The non custodial wants to keep pushing the issue of getting more visitation time when they have only just started seeing the child 1 month ago, but say's it has nothing to do with reducing the child support,the noncustodial also keeps stating that they want shared custody despite the fact that their child is doing well witht the other parent.The child is only two years old and has never lived with this noncustodial parent but the NCP is insisten on taking the child out of the home of the custodial parent for half of the week despite how well this child is doing. So my question again is ,can the NCP change the custody arrangement that is already established just because they want more custody?Can sole physical custody be changed to shared custody?You didn't make this baby on its own. That child is half the father's, not just yours and it is in the child's best interest that they are able to form a healthy attachment with their father. It's very easy for a mother to start thinking in term's of what is best for them rather than what is best for their child. But this is not about what the mother wants, this is about the importance of fostering and encouraging a healthy relationship with both parents.