pip ..is this usual?

hi, on a transfer from dla to pip after sending in the form tor someone for you then to be rung up about the claimants ability to perform in an assessment. They rang checked I was his primary carer and then said he will need help, he needs a home visit and will he become aggressive under stress. I was then told I would get a letter about a home appointment in a few weeks. That hasn't arrived but a different letter has. It says looking at your claim we have or are waiting for evidence from the contacts you have provided. you may need a medical.