Wetsuit for an invalid ?

An elderly friend, who has no interest in scuba or snorkeling, seeks
advice.

For exercise he leaves his house and walks outside to and from his
heated pool.

For the cold weather he would like advice on what kind of jacket or
wetsuit top he could buy or have custom adjusted so that it would be
easy for him to get into and out of. [For example, zippers not only in
the front of the chest, but also up each arm.]

He would don the jacket in his house, swim with it on, and remove it
only when he had reentered the warmth of his house.

Thank you for your help.

--
Pat