Can you get temporary custody of your child if the other parent has filed for custody in pennsylvania?

The mother of my husbands child has filed for custody and neither of them currently have custody but the baby lives with her mother because she never lets my husband take her and we live in chattanooga, tn while they live in lancaster, pa. The baby has been in the hospital about 4 times in the past 6 months twice because of negligence of the mother and the most recent time was because she had a very bad flu but the doctors also found what looked to be an std and we have other reason to believe that she in fact has been ually violated while in her care and were also wondering if it would now be too late to call dhs because the mother has gone and filed for custody we don't want it to look like a sick plea for rights or something we sincerely were thinking of doing this about a week ago and now this happens today. We also were wondering about the fact that we're in a different state than the custody was filed in; would that affect our chances of receiving temporary or even physical custody in the long run? thank you so much for all your help in advanced!