I've always been a little conflicted about my mum riding horses. She has lost a lot of weight since I was a lot younger, but she has sort of petered out and hasn't lost weight. I don't remember how much she weighs, but I think she weighs around 240-260 and is 5'9"ish. Maybe a little more recently. Now, I know this isn't a very heavy weight, but I always feel sensitive about weight on the horse's back. Particularly because my mum isn't the best of riders. She understands and can put out the appropriate skills for walking and minor maneuvering from (minor riding) in her younger years and watching/assisting me over so many year(going through lessons, clinics, trainers and whatnot), but that is about her extent.
Now, if I had a much more broke horse for her to ride, I would less worried, but the very small array of horses I have I feel concerned. My gelding, who is big enough to hold her(16h), has a club foot, and while it's never bothered him with riding(I'm 4'11" and 112 lbs), I get super protective of him. As well as his "pleasure" breeding, his back is a little on the longer side and I don't want to strain him much, especially since he isn't conditioned at all right now.
Then my other horse is a three year old mare. She is pretty thick and has a nice, short back and big strong hip, but she is only about 14.2-14.3. I know this height is capable of carrying larger loads as well, but I am concerned more by her age.
I'd personally feel more comfortable with her riding a larger, well...doesn't have to be larger, but stockier breed horse(say a draft cross even), but with a 7 mo old colt in hand as well, we cannot afford another horse, but are unwilling to sell/trade any of the three we are keeping.
I am conflicted because I don't want to say no to my mum and riding because I know she wants to, but her lack of will(she's very strong headed and stuck in her ways) I doubt she will be actively seeking to lose weight, keeps me worried for the horses in the long term.
Am I worrying too much and should let her ride freely or should I feel as concerned as I do? Am I just babying my horses too much(underestimating)?