Do not change his routine right now. The heat is stress enough. You do not need him to start pacing or calling because he is unfamiliar with the circumstances.
The outside pen for the foal is out of the question now. My BM says that if I set up one, everybody will want one for their horse. I understand. I even offered to buy the fence panels. It would have been in a place that he knows because I lead him out there every day to graze, and he can see the geldings in their pasture about 100 yards away. He wouldn't be out there unsupervised.
Anyway, I have been going out twice a day in the p.m. hours to take him out. Beginning tomorrow, school year is approaching so I have at least 1/2 days preparing for the year at my job. Thank goodness my barn is only 10 minutes from my job and I can get over there after school business is taken care of. BM hosed him off yesterday a.m. and he did great with that! The little guy loves water. So we will make that a part of his routine, too.