Leaning to one side whilst sitting

Has anyone ever come across the situation where the person that they care for (adult) leans significantly to one side when they are sitting or standing? Other than using cushions or pillows to stabilise them and make them sit up a little straighter, are there any aids/OT aids etc that could be used when sitting? My father is wheelchair bound, and I am afraid he might slip out of his wheelchair as he seems to no longer be able to sit up straight stably. Many thanks!

There needs to be a home visit for an O/T. Contact your G.P to make a referral A.S.A.P. There should be a visit to the G.P. to check balance issues. It could be one of many different things.

Has there been a recent hearing test.
Has there been a ear wax check.

How long has this been happening.