Helping Dad to Bed

For the past couple of weeks when helping Dad to bed I have noticed he places himself oddly, into an L shape. He can no longer roll, shuffle himself in the bed. Last night, he got into bed, was in an L shape so I asked him to get out of bed again. Sat him on the edge, and helped him down onto his side and swung his legs across. He was now on his side and laying straight. He said 'that's a lot more comfy' and he had a better sleep. What concerns me is that he can, some nights, get up to urinate, maybe 10 times. So on these nights he is getting back into bed into an L shape. I think all I can do is, if I hear him, help him position himself back into bed.
The positive side is that he is still mobile and that I am thankful for.