Of course. The only reason a bail bondsman is used is because the people involved don’t have all the monies required to bail a person out. There is no law or professional issue regarding this.
There is no law against someone using HIS OWN money to bail anyone he wants.
If the court aprove a bail then anyone is free to pay for the bill. It would be unconstitutional to forbid anyone from bailing a friend (or whoever that person wants to bail out).