All seats at Lucas Oil Stadium are 20-21 inches wide which is typical for an NFL stadium. Seat 1 in your ticket group is an aisle seat which does allow for a little extra legroom and no seat on one side. However, it will probably be a tough fit.
Elevators are available to all levels of Lucas Oil Stadium, but you are advised to contact the ticket office ahead of time - (317) 297-7000 - to make arrangements. You may also be able to request accessible and companion seating for you and your guest from the ticket office.
Please be aware that row 19 in section 628 requires a hike up a very steep set of stairs. The stairs may be difficult or intimidating for some guests.