If FMLA ailment limits work hours, does that affect employee’s other PT job?

Q. “An employee works part time for us and has another part-time job on the side. He has applied for FMLA and come back with limitations from his doctor on his paperwork. If those limitations are that he can only work a set number of hours and he works them here--and then goes to work at his other part-time job, is that grounds for termination?" -- Cole, Minnesota