Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry that Alfie is having this issue. While I don't become too concerned if a dog doesn't have a daily bowel movement, if several days go by without the production of one, I do worry that constipation issues may develop.
It's possible that feeding him other over the counter oral laxatives may help to soften his stools enough where he doesn't have to strain or stand for a long period of time. We wouldn't want to cause diarrhea but perhaps just a softer stool. Options to consider include the following:
1. Cat laxatives such as Laxatone or Laxaire which can work fairly well on the smaller dogs. These are brand names but every pet or grain store should carry them. I tend to dose at 1 inch three times a day.
2. Human Miralax which can be added to his food (and hopefully, he won't detect it) at a dose of 1/4th-1/2th teaspoon daily.
3. Colace at a dose of 25 mg once or twice daily. I'd probably only use it for 1-2 days, though.
I'd also try to support him with a towel wrapped around his mid section if you aren't already doing so. If he doesn't have to support his entire weight, then it may find it more comfortable to produce stool.
I hope this helps. Deb